NOVELTY - 2-(3-(1-Cyano-1-methylethyl)-5-(hydroxymethyl)phenyl)-2-methylpropanenitrile, halide or methanesulfonyl chloride, and a base are reacted. Saturated sodium bicarbonate solution is added, the reaction mixture is allowed to stand, and the obtained organic phase is recrystallized to obtain a compound (I) by substituting hydroxyl group of 2-(3-(1-cyano-1-methylethyl)-5-(hydroxymethyl)phenyl)-2-methylpropanenitrile by chloro, bromo, tosyl or mesyl group. The obtained compound and 1,2,4-triazole are coupled, and separated organic phase is recrystallized to obtain anastrozole.    USE - Preparation of anastrozole (claimed).    ADVANTAGE - The method enables preparation of anastrozole with high selectivity and yield, without separation problems of side products. The consumption of expensive raw materials or catalysts is prevented. The difficulty of synthesis of raw materials is solved, and the total number of reaction steps is reduced. The process conditions are stable and mild, and the method is simple, environmentally-friendly, and suitable for large-scale production.    DETAILED DESCRIPTION - In the presence of a halogenated hydrocarbon solvent, 3,5-dimethylbenzoic acid ethyl ester is heat-refluxed. A brominating agent is added to the system and reacted for 4-8 hours at reflux temperature, and the reaction mixture is cooled to 20-30 degrees C. Saturated sodium hydrogen sulfite is added to terminate the reaction solution, the reaction mixture is allowed to stand, and organic phase is separated. The organic phase is added to a recrystallization solvent to obtain 3-bromomethyl-5-methyl-benzoic acid ethyl ester. In the presence of a halogenated hydrocarbon solvent, the obtained compound and a brominating reagent are heat-refluxed, reacted for 4-8 hours,and cooled to 20-30 degrees C. Reaction is terminated using saturated sodium hydrogen sulfite, the reaction mixture is allowed to stand, and the separated organic phase is added to a recrystallization solvent to obtain 3,5-bis-bromomethyl-benzoic acid ethyl ester with a purity of 94.5-95.6% and yield of 65-80%. In the presence of a halogenated hydrocarbon solvent, cyanide is added to buffer solution, the reaction mixture is heat-refluxed, and the obtained compound is added. The contents are reacted for 10-20 hours, cooled to 20-30 degrees C, and allowed to stand. The organic phase is added to a recrystallization solvent to obtain ethyl 3,5-bis(cyanomethyl)benzoate with a purity of 97.2-98% and a yield of 66-85%. The molar ratio of 3,5-bis-bromomethyl-benzoic acid ethyl ester and cyanide is 1:2-5. The ratio of 3,5-bis-bromomethyl-benzoic acid ethyl ester and recrystallization solvent is 1 g/5-15 mL. In the presence of ether or amide solvent, at 0-10 degrees C, the obtained compound, alkali cyanide, and methylating agent are reacted for 1-5 hours. Saturated brine and methyl t-butyl ether are added, the reaction mixture is allowed to stand, and organic phase is added to recrystallization solvent to obtain ethyl 3,5-bis(1-cyano-1-methylethyl)benzoate with a purity of 94.2-95.2% and a yield of 86-96%. The ratio of ethyl 3,5-bis(cyanomethyl)benzoate and amide or ether solvent is 1 g/10-30 mL. The molar ratio of ethyl 3,5-bis(cyanomethyl)benzoateand alkali cyanide is 1:5-10. The molar ratio of ethyl 3,5-bis(cyanomethyl)benzoate and methylating agent is 1:5-10. The ratio of ethyl 3,5-bis(cyanomethyl)benzoate and saturated brine is 1 g/10-30 mL. The ratio of ethyl 3,5-bis(cyanomethyl)benzoate and methyl t-butyl ether is 1 g/20-40 mL. The ratio of ethyl 3,5-bis(cyanomethyl)benzoate and recrystallization solvent is 1 g/5-15 mL. In the presence of ether or alcohol solvent, at 20-30 degrees C the obtained compound, activated carbon, and reducing agent are heat-refluxed for 1-5 hours, pH is adjusted to 5-6 using 1N hydrochloric acid solution, ethyl acetate is added, and the reaction mixture is allowed to stand. The organic phase is added to recrystallization solvent to obtain 2-(3-(1-cyano-1-methylethyl)-5-(hydroxymethyl)phenyl)-2-methylpropanenitrile with a purity of 94.3-96.3% and a yield of 85-96%. The ratio of ethyl 3,5-bis(1-cyano-1-methylethyl)benzoate and alcoholic or ether solvent is 1 g/5-15 mL. The molar ratio of ethyl 3,5-bis(1-cyano-1-methylethyl)benzoate and reducing agent is 1:1-4. The ratio of ethyl 3,5-bis(1-cyano-1-methylethyl)benzoate and activated carbon is 0.1 g/g. The ratio of ethyl 3,5-bis(1-cyano-1-methylethyl)benzoate and ethyl acetate is 1 g/10-20 mL. The ratio of ethyl 3,5-bis(1-cyano-1-methylethyl)benzoate and recrystallization solvent is 1 g/5-15 mL. In the presence of a halogenated hydrocarbon solvent, at 20-30 degrees C, 2-(3-(1-cyano-1-methylethyl)-5-(hydroxymethyl)phenyl)-2-methylpropanenitrile, halide or methanesulfonyl chloride, and a base are reacted for 1-5 hours. Saturated sodium bicarbonate solution is added until the pH is 7-8, the reaction mixture is allowed to stand, and the obtained organic phase is added to a recrystallization solvent to obtain a compound of formula (I) by substituting hydroxyl group of 2-(3-(1-cyano-1-methylethyl)-5-(hydroxymethyl)phenyl)-2-methylpropanenitrile by chloro, bromo, tosyl or mesyl group, with a purity of 95.6-99.5% and a yield of 89-94%. The ratio of 2-(3-(1-cyano-1-methylethyl)-5-(hydroxymethyl)phenyl)-2-methylpropanenitrile and halogenated hydrocarbon solvent is 1 g/3-8 mL. The molar ratio of 2-(3-(1-cyano-1-methylethyl)-5-(hydroxymethyl)phenyl)-2-methylpropanenitrile and halide is 1:0.5-2. The molar ratio of 2-(3-(1-cyano-1-methylethyl)-5-(hydroxymethyl)phenyl)-2-methylpropanenitrile and methanesulfonyl chloride is 1:1-3. The molar ratio of 2-(3-(1-cyano-1-methylethyl)-5-(hydroxymethyl)phenyl)-2-methylpropanenitrile and base is 1:1-3. The ratio of 2-(3-(1-cyano-1-methylethyl)-5-(hydroxymethyl)phenyl)-2-methylpropanenitrile and recrystallization solvent is 1 g/5-15 mL. In the presence of an amide solvent, at 0-40 degrees C, the obtained compound and 1,2,4-triazole are coupled for 2-10 hours, ethyl acetate and saturated brine are added, and the reaction mixture is allowed to stand. The obtained organic phase is added to recrystallization solvent to obtain anastrozole with a purity of 99.6-99.8% and a yield of 33-45%. The ratio of compound (I) and amide solvent is 1 g/10-30 mL. The molar ratio of compound (I) and 1,2,4-triazole is 1:0.9-2. The molar ratio of compound (I) and base is 1:0.9-2. The ratio of compound (I) and saturated brine is 1 g/10-30 mL. The ratio of compound (I) and ethyl acetate is 1 g/20-40 mL. The ratio of compound (I) and recrystallization solvent is 1 g/5-15 mL.    X=Cl, Br, OTs or OMs.