NOVELTY - Processing agricultural straw comprises adding the straw into a small section and then washing with water, stirring, filtering in a vacuum pump, drying in a drying box and crushing, mixing the straw powder with sodium hydroxide solution and then swelling, centrifuging, filtering, and drying, mixing the obtained mixture with water and propylene oxide in a reaction kettle and then sealing, introducing nitrogen gas in the kettle and then discharging, stirring the mixture in a stirring device and then heating, reacting and cooling, opening the reaction kettle, and filtering the reaction product.    USE - The method is useful for processing agricultural straw (claimed) to produce solid adsorbent product and coal water slurry dispersant products.    ADVANTAGE - The method is capable of processing the agricultural straw with good absorption effect.    DETAILED DESCRIPTION - Processing agricultural straw comprises (1) adding the straw into a small section and then washing with water for 2-3 times, stirring, filtering in a vacuum pump until the filtrate is clear, drying in a drying box at 55 degrees C for 24-48 hours and crushing into 100 meshes sieve to obtain straw powder, (2) mixing the straw powder with 0.01-0.09 mole/l of sodium hydroxide solution and then swelling by swelling treatment for 48-64 hours to adjust pH value to 6.6-7.4, centrifuging, filtering, drying in the drying box at 65 degrees C for 24-48 hours to obtain front rear treatment of straw powder, (3) weighing the obtained step in (2) and then mixing with deionized water and propylene oxide according to a weight ratio of 5-20:500-1500:3-5 in a reaction kettle and then sealing, introducing nitrogen gas in the kettle for 20-60 minutes and then discharging, stirring the mixture in a magnetic stirring device and then heating in an electric furnace reaction kettle at 220-250 degrees C, reacting and cooling to 180 degrees C, opening the reaction kettle, filtering the reaction product to obtain liquid phase product and rear solid phase product, drying the rear solid phase product at 110-120 degrees C for 26-36 hours and then carbonizing by silicon carbide treatment to obtain solid material, (4) dissolving 3-chloro-2-hydroxypropyl trimethylammonium chloride in isopropanol-water mixed solution according to a weight ratio of 5-10:16-23:200-230 to form a mixed solution A, adding the solid material into the mixed solution A and then stirring at 30-65 degrees C and reacting for 12-20 hours, filtering the solution in rear reaction system to adjust a pH value to 6.5-7 to obtain solid product, adding the solid product and then washing with water for 2-3 times and reacting at 110-120 degrees C for 26-48 hours to obtain 3-chloro-2-hydroxypropyl trimethylammonium chloride modified of solid product, mixing chloroacetic acid in ethanol-water mixed solution according to a mass ratio of 4-9:20-100:20-98 and then dissolving to obtain a mixed solution B and then stirring, reacting at temperature of 40-80 degrees C for 13-24 hours, filtering the solution in rear reaction system to adjust a pH value to 6.6-7.5 to obtain rear filter of solid product and then washing with water for 5-9 times and reacting at 110-115 degrees C for 30-72 hours to obtain solid adsorbent product, and (e) adding the obtained in step (3) to adjust a pH value of liquid phase product to 12-12.8 and then stirring at 75 degrees C, mixing with formaldehyde, reacting by condensation reaction for 2 hours and reducing at temperature to 90 degrees C, adding sodium sulfite and then reacting by sulfonation reaction process for 2-3 hours, cooling to normal temperature and discharging. The mass ratio of the: 3-chloro-2-hydroxypropyl trimethylammonium chloride and the solid material is 1-3:5-10; modified solid product and mixed solution B is 5-10: 6-12.