TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Method: The method comprises either (a) adding perchloric acid as a catalyst, acetylating anhydrous glucose by adding acetic anhydride to produce peracetyl glucose, and controlling the temperature at 35 degrees C, detecting the reaction endpoint by thin-layer chromatography (TLC), finishing acetylation, passing gas to hydrogen bromide, controlling the temperature at 30 degrees C, and brominating hemiacetal hydroxy group of peracetyl glucose to produce monobromo tetraacetyl glucose, where the molar ratio of anhydrous glucose to acetic anhydride to perchloric acid to hydrogen bromide is 1:7.5:0.04:0.76; (b) adding a two-phase system containing chloroform and water in the volume ratio of 1:1, adding tetra-butyl ammonia bromide as a catalyst, carbonate and p-hydroxybenzaldehyde to the two-phase system, controlling the temperature at 60 degrees C, then dissolving monobromo tetraacetyl glucose solution by adding chloroform dropwise, where the weight ratio of monobromo tetraacetyl glucose to p-hydroxybenzaldehyde is 1:0.9, monitoring the end point of the reaction by TLC to obtain a condensed compound 4-formylphenyl-2',3',4',6'-tetraacetyl- beta -D-glucopyranose, and re-crystallizing the condensed compound by 95% ethanol, where the molar ratio of monobromo tetraacetyl glucose to p-hydroxy benzaldehyde to carbonate to tetra-butyl ammonia bromide is 1:0.9:1:0.3; (c) adding the condensed compound to a hydrogen absorption solvent, then adding Raney nickel (RTM: Nickel-aluminum alloy catalyst) or palladium carbon with an amount of 30% the weight of the condensed compound, passing hydrogen gas, pressurizing the material at 0.5 MPa, hydrogenating the material, controlling the temperature at 40 degrees C, and reacting for 6 hours, where the volume/weight ratio of the hydrogen absorption solvent to the condensed compound is 5:1; (d) hydrogenating, filtering, adding sodium alkoxide or ammonia to the filtrate, removing the protective group, reacting for 4 hours at 18 degrees C, detecting by TLC until the reaction is completed, carrying out vacuum drying, and concentrating the filtrate to obtain gastrodin, where the mass ratio of the sodium alkoxide to 4-formylphenyl-2',3',4',6'-tetraacetyl- beta -D-glucopyranose is 1:100, and the mass ratio of ammonia to 4-formylphenyl-2',3',4',6'-tetraacetyl- beta -D-glucopyranose is 2:100; and (e) re-crystallizing gastrodin by taking alcohol or a mixed solvent of alcohol and ester or a mixed solvent of alcohol and ketone as a re-crystallizing solvent, to obtain pure gastrodin, where the volume/weight ratio of the re-crystallizing solvent to gastrodin is 4:1; or (f) adding perchloric acid as a catalyst, acetylating anhydrous glucose by adding acetic anhydride to produce peracetyl glucose, and controlling the temperature at 32 degrees C, detecting the reaction endpoint by TLC, finishing acetylation, passing gas to hydrogen bromide, controlling the temperature at 28 degrees C, and brominating hemiacetal hydroxy group of peracetyl glucose to produce monobromo tetraacetyl glucose, where the molar ratio of anhydrous glucose to acetic anhydride to perchloric acid to hydrogen bromide is 1:7.5:0.04:0.76; (g) adding a two-phase system containing chloroform and water in the volume ratio of 1:1, adding tetra-butyl ammonia bromide as a catalyst, carbonate and p-hydroxybenzaldehyde to the two-phase system, controlling the temperature at 55 degrees C, then dissolving monobromo tetraacetyl glucose solution by adding chloroform dropwise, where the weight ratio of monobromo tetraacetyl glucose to p-hydroxybenzaldehyde is 1:1, monitoring the end point of the reaction by TLC to obtain a condensed compound 4-formylphenyl-2',3',4',6'-tetraacetyl- beta -D-glucopyranose, and re-crystallizing the condensed compound by 95% ethanol, where the molar ratio of monobromo tetraacetyl glucose to p-hydroxy benzaldehyde to carbonate to tetra-butyl ammonia bromide is 1:1:1.1:0.3; (h) adding the condensed compound to a hydrogen absorption solvent, then adding Raney nickel (RTM: Nickel-aluminum alloy catalyst) or palladium carbon with an amount of 25% the weight of the condensed compound, passing hydrogen gas, pressurizing the material at 0.5 MPa, hydrogenating the material, controlling the temperature at 40 degrees C, and reacting for 6 hours, where the volume/weight ratio of the hydrogen absorption solvent to the condensed compound is 6:1; (i) hydrogenating, filtering, adding sodium alkoxide or ammonia to the filtrate, removing the protective group, reacting for 3-4 hours at 18-25 degrees C, detecting by TLC till the reaction is completed, carrying out vacuum drying, and concentrating the filtrate to obtain gastrodin, where the mass ratio of the sodium alkoxide to 4-formylphenyl-2',3',4',6'-tetraacetyl- beta -D-glucopyranose is 2:100, and the mass ratio of ammonia to 4-formylphenyl-2',3',4',6'-tetraacetyl- beta -D-glucopyranose is 3:100; and (j) re-crystallizing gastrodin by taking alcohol or a mixed solvent of alcohol and ester or a mixed solvent of alcohol and ketone as a re-crystallizing solvent, to obtain pure gastrodin, where the volume/weight ratio of the re-crystallizing solvent to gastrodin is 5:1; or (k) adding perchloric acid as a catalyst, acetylating anhydrous glucose by adding acetic anhydride to produce peracetyl glucose, and controlling the temperature at 31 degrees C, detecting the reaction end point by TLC, finishing acetylation, passing gas to hydrogen bromide, controlling the temperature at 27 degrees C, and brominating hemiacetal hydroxy group of peracetyl glucose to produce monobromo tetraacetyl glucose, where the molar ratio of anhydrous glucose to acetic anhydride to perchloric acid to hydrogen bromide is 1:7.5:0.04:0.76; (l) adding a two-phase system containing chloroform and water in the volume ratio of 1:1, adding tetra-butyl ammonia bromide as a catalyst, carbonate and p-hydroxybenzaldehyde to the two-phase system, controlling the temperature at 50 degrees C, then dissolving monobromo tetraacetyl glucose solution by adding chloroform dropwise, where the weight ratio of monobromo tetraacetyl glucose to p-hydroxybenzaldehyde is 1:1, monitoring the end point of the reaction by TLC to obtain a condensed compound 4-formylphenyl-2',3',4',6'-tetraacetyl- beta -D-glucopyranose, and re-crystallizing the condensed compound by 95% ethanol, where the molar ratio of monobromo tetraacetyl glucose to p-hydroxy benzaldehyde to carbonate to tetra-butyl ammonia bromide is 11:1.1:1.15:0.3; (m) adding the condensed compound to a hydrogen absorption solvent, then adding Raney nickel (RTM: Nickel-aluminum alloy catalyst) or palladium carbon with an amount of 20% the weight of the condensed compound, passing hydrogen gas, pressurizing the material at 0.5 MPa, hydrogenating the material, controlling the temperature at 34 degrees C, and reacting for 6 hours, where the volume/weight ratio of the hydrogen absorption solvent to the condensed compound is 8:1; (n) hydrogenating, filtering, adding sodium alkoxide or ammonia to the filtrate, removing the protective group, reacting for 3-4 hours at 18-25 degrees C, detecting by TLC until the reaction is completed, carrying out vacuum drying, and concentrating the filtrate to obtain gastrodin, where the mass ratio of the sodium alkoxide to 4-formylphenyl-2',3',4',6'-tetraacetyl- beta -D-glucopyranose is 1:100, and the mass ratio of ammonia to 4-formylphenyl-2',3',4',6'-tetraacetyl- beta -D-glucopyranose is 4:100; and (o) re-crystallizing gastrodin by taking alcohol or a mixed solvent of alcohol and ester or a mixed solvent of alcohol and ketone as a re-crystallizing solvent, to obtain pure gastrodin, where the volume/weight ratio of the re-crystallizing solvent to gastrodin is 6:1; or (p) adding perchloric acid as a catalyst, acetylating anhydrous glucose by adding acetic anhydride to produce peracetyl glucose, and controlling the temperature at 30 degrees C, detecting the reaction endpoint by TLC, finishing acetylation, passing gas to hydrogen bromide, controlling the temperature at 25 degrees C, and brominating hemiacetal hydroxy group of peracetyl glucose to produce monobromo tetraacetyl glucose, where the molar ratio of anhydrous glucose to acetic anhydride to perchloric acid to hydrogen bromide is 1:7.5:0.04:0.76; (q) adding a two-phase system containing chloroform and water in the volume ratio of 1:1, adding tetra-butyl ammonia bromide as a catalyst, carbonate and p-hydroxybenzaldehyde to the two-phase system, controlling the temperature at 40 degrees C, then dissolving monobromo tetraacetyl glucose solution by adding chloroform dropwise, where the weight ratio of monobromo tetraacetyl glucose to p-hydroxybenzaldehyde is 1:1.2, monitoring the end point of the reaction by TLC to obtain a condensed compound 4-formylphenyl-2',3',4',6'-tetraacetyl- beta -D-glucopyranose, and re-crystallizing the condensed compound by 95% ethanol, where the molar ratio of monobromo tetraacetyl glucose to p-hydroxy benzaldehyde to carbonate to tetra-butyl ammonia bromide is 1:1.2:1.2: 0.3; (r) adding the condensed compound to a hydrogen absorption solvent, then adding Raney nickel (RTM: Nickel-aluminum alloy catalyst) or palladium carbon with an amount of 15% the weight of the condensed compound, passing hydrogen gas, pressurizing the material at 0.5 MPa, hydrogenating the material, controlling the temperature at 30 degrees C, and reacting for 6 hours, where the volume/weight ratio of the hydrogen absorption solvent to the condensed compound is 10:1; (s) hydrogenating, filtering, adding sodium alkoxide or ammonia to the filtrate, removing the protective group, reacting for 3-4 hours at 18-25 degrees C, detecting by TLC until the reaction is completed, carrying out vacuum drying, and concentrating the filtrate to obtain gastrodin, where the mass ratio of the sodium alkoxide to 4-formylphenyl-2',3',4',6'-tetraacetyl- beta -D-glucopyranose is 3:100, and the mass ratio of ammonia to 4-formylphenyl-2',3',4',6'-tetraacetyl- beta -D-glucopyranose is 5:100; and (t) re-crystallizing gastrodin by taking alcohol or a mixed solvent of alcohol and ester or a mixed solvent of alcohol and ketone as a re-crystallizing solvent, to obtain pure gastrodin, where the volume/weight ratio of the re-crystallizing solvent to gastrodin is 7:1. The method further comprises either (I) adding acetic anhydride (425 ml) and perchloric acid (2.5 g) to a reaction bottle, then adding anhydrous glucose (108 g) in batches to the bottle, completely adding the glucose in 30 minutes, controlling the temperature at 35 degrees C, detecting the reaction end point by TLC, directly, and slowly passing hydrogen bromide (0.013 m3) to the reaction bottle, controlling the temperature at 30 degrees C, detecting the reaction by TLC, directly pouring the reaction solution to ice water after finishing the reaction, stirring the solution for 15 minutes in ice bath, then filtering the solution, washing the solution by cold water until the solution is neutral, and obtaining monobromo tetraacetyl glucose (197 g) containing 80% of glucose; (II) adding potassium carbonate (30.4 g), p-hydroxy benzaldehyde (26.8 g) and tetra-butyl ammonia bromide (19.3 g) to a reaction container, then adding water (300 ml) and chloroform (200 ml), heating at 50 degrees C, dissolving monobromo tetraacetyl glucose (82.2 g) to chloroform (100 ml), adding to the reaction solution in dropwise manner, controlling the dripping speed, and adding dropwise for 30 minutes, thermal insulating, reacting for 3 hours, detecting the reaction end point by TLC, stopping to heat, and cooling to 15 degrees C, layering the solution, extracting the aqueous layer by chloroform (100 ml) once, mixing the chloroform extracted solution twice, washing with 10% sodium hydroxide solution (150 ml), washing with saturated saline solution (150 ml), drying by adding anhydrous sodium sulfate (8 g), then evaporating the product in a rotary manner, removing chloroform, adding 95% ethanol (150 ml) under ice bath condition, stirring for 2 hours, and filtering the solution to obtain condensed compound (40 g) containing monobromo tetraacetyl glucose (44.2%); and (III) adding condensed compound (20 g) to a high pressure reaction kettle, adding anhydrous ethanol (140 ml) and W-2 type Raney nickel (RTM: Nickel-aluminum alloy catalyst) (4 g), passing hydrogen gas at 40 degrees C until the pressure reaches 0.5 MPa, reacting for 6 hours, filtering the solution when the solution is hot, removing Raney nickel (RTM: Nickel-aluminum alloy catalyst), directly adding sodium ethoxide (0.3 g) to the filtrate, magnetically stirring for 3 hours at 18-25 degrees C, filtering, evaporating the solution in rotary manner, removing anhydrous ethanol to obtain a crude product of gastrodin, re-crystallizing the crude product by a mixed solvent of ethyl acetate and methanol according to ratio of 1:1 to obtain gastrodin (12.3 g) containing condensed compound (94.2%), and the total yield is 33.3%; or (IV) adding acetic anhydride (425 ml) and perchloric acid (2.5 g) to a reaction bottle, then adding anhydrous glucose (108 g) in batches to the bottle, completely adding the glucose in 30 minutes, controlling the temperature at 30 degrees C, detecting the reaction endpoint by TLC, directly, and slowly passing hydrogen bromide (0.013 m3) to the reaction bottle, controlling the temperature at 25 degrees C, detecting the reaction by TLC, directly pouring the reaction solution to ice water after finishing the reaction, stirring the solution for 15 minutes in ice bath, then filtering the solution, washing the solution by cold water until the solution is neutral, and obtaining monobromo tetraacetyl glucose (197 g) containing 80% of glucose; (V) adding sodium carbonate (25.4 g), p-hydroxy benzaldehyde (58.5 g) and tetra-butyl ammonia bromide (19.3 g) to a reaction container, then adding water (300 ml) and chloroform (200 ml), heating at 45 degrees C, dissolving monobromo tetraacetyl glucose (82.2 g) to chloroform (100 ml), adding to the reaction solution in dropwise manner, controlling the dripping speed, and adding dropwise for 30 minutes, thermal insulating, reacting for 3 hours, detecting the reaction endpoint by TLC, stopping to heat, and cooling to 15 degrees C, layering the solution, extracting the aqueous layer by chloroform (100 ml) once, mixing the chloroform extracted solution twice, washing with 10% sodium hydroxide solution (130 ml), washing once with saturated saline solution (200 ml), drying by adding anhydrous sodium sulfate (8 g), then evaporating the product in a rotary manner, removing chloroform, adding 95% ethanol (300 ml) under ice bath condition, stirring for 2 hours, and filtering the solution to obtain condensed compound (41 g) containing monobromo tetraacetyl glucose (45.3%); and (VI) adding condensed compound (20 g) to a high pressure reaction kettle, adding methanol (160 ml) and W-1 type Raney nickel (RTM: Nickel-aluminum alloy catalyst) (5 g), passing hydrogen gas at 35 degrees C until the pressure reaches 0.5 MPa, reacting for 6 hours, filtering the solution when the solution is hot, removing Raney nickel (RTM: Nickel-aluminum alloy catalyst), directly adding sodium methoxide (0.4 g) to the filtrate, magnetically stirring for 4 hours at 18-25 degrees C, filtering, evaporating the solution in rotary manner, removing anhydrous ethanol to obtain a crude product of gastrodin, re-crystallizing the crude product by a mixed solvent of anhydrous ethanol and acetone (100 ml) according to ratio of 3:1 to obtain gastrodin (12.2 g) containing condensed compound (93.5%), and the total yield is 33.9%; or (VII) adding acetic anhydride (425 ml) and perchloric acid (2.5 g) to a reaction bottle, then adding anhydrous glucose (108 g) in batches to the bottle, completely adding the glucose in 30 minutes, controlling the temperature at 35 degrees C, detecting the reaction endpoint by TLC, directly, and slowly passing hydrogen bromide (0.013 m3) to the reaction bottle, controlling the temperature at 25 degrees C, detecting the reaction by TLC, directly pouring the reaction solution to ice water after finishing the reaction, stirring the solution for 10-15 minutes in ice bath, then filtering the solution, washing the solution by cold water until the solution is neutral, and obtaining monobromo tetraacetyl glucose (197 g) containing 80% of glucose; (VIII) adding sodium bicarbonate (20.1 g), p-hydroxy benzaldehyde (30.6 g) and tetra-butyl ammonia bromide (19.3 g) to a reaction container, then adding water (300 ml) and chloroform (200 ml), heating at 45 degrees C, dissolving monobromo tetraacetyl glucose (82.2 g) to chloroform (100 ml), adding to the reaction solution in dropwise manner, controlling the dripping speed, and adding dropwise for 30 minutes, thermal insulating, reacting for 3 hours, detecting the reaction end point by TLC, stopping to heat, and cooling to 15 degrees C, layering the solution, extracting the aqueous layer by chloroform (100 ml) once, mixing the chloroform extracted solution twice, washing with 10% sodium hydroxide solution (130 ml), washing once with saturated saline solution (200 ml), drying by adding anhydrous sodium sulfate (8 g), then evaporating the product in a rotary manner, removing chloroform, adding 95% ethanol (300 ml) under ice bath condition, stirring for 2 hours, and filtering the solution to obtain condensed compound (41 g) containing monobromo tetraacetyl glucose (45.3%); and (IX) adding condensed compound (20 g) to a high pressure reaction kettle, adding acetone (200 ml) and 10% palladium carbon (4 g), passing hydrogen gas at 30 degrees C until the pressure reaches 0.5 MPa, reacting for 6 hours, filtering the solution when the solution is hot, removing Raney nickel (RTM: Nickel-aluminum alloy catalyst), directly adding sodium methoxide (0.4 g) to the filtrate, magnetically stirring for 4 hours, filtering, evaporating the solution in rotary manner, removing acetone to obtain a crude product of gastrodin, re-crystallizing the crude product by anhydrous ethanol (100 ml), drying the product, and obtaining gastrodin (12.6 g) containing condensed compound (96.5%), and the total yield is 34.9%.