NOVELTY - Preparing sinomenine slow release injection, comprises (1) extracting caulis sinomenii rough powder with hydrochloric acid, filling the solution and medicine powder in a percolation cylinder to obtain percolation liquid, sampling the percolated liquid in cation exchange resin, sinking resin by ammonia solution, neutralizing the pH, and concentrating and drying to obtain sinomenine product (2) taking beef albumin, sinomenine, and (3) adding water, dissolving and spray drying the solution to obtain white powder microballoon and then putting in a baking box and heating.    USE - The method is useful for preparing sinomenine slow release injection.    ADVANTAGE - The method is capable of simply preparing the sinomenine slow release injection with high purity in an environmentally friendly manner.    DETAILED DESCRIPTION - Preparing sinomenine slow release injection, comprises: (1) (i) extracting 100-1000 parts by weight (pbw) of caulis sinomenii rough powder by 60-1000 parts by volume (pbv) of 0.1-1 mole/l hydrochloric acid for 0.5-8 hours, filling the solution and a medicine powder which is dipped for 6-48 hours to get liquid face in a percolation cylinder, and percolating at 2-5 ml/minutes for 6-24 hours to obtain percolation liquid, (ii) sampling the percolated liquid in cation exchange resin or 152 resin with diameter height ratio of 1:8-12 of 2-5 times volume/hours till flowing liquid precipitate, and checking by silicotungstic acid test solution and then stopping the sampling, when the thin-layer chromatography detects alkali spot, washing the solution by purified water, sinking the resin by 8-15% of ammonia solution or 3-10% of hydrochloric acid for 12 hours and then washing by ammonia water-ethanol solution or 152-type resin or washing resin by 3-10% of hydrochloric acid at 2-5 BV/hours, receiving the washing solution while checking precipitate by silicotungstic acid test solution and stopping receiving the washing solution while checking precipitate by silicotungstic acid test solution, combining the washing solution and neutralizing the pH (6-8) by hydrochloric acid or ammonia water, removing salt, and concentrating and then drying to obtain sinomenine product; (2) taking 1000-4000 pbw of beef albumin or human serum albumin and 500-2000 pbw of sinomenine; and (3) adding 80-150 pbv of water to obtain clean solution after completely dissolving and then spray drying the solution by a spray dryer to obtain white powder microballoon, collecting the microballoon and then putting in a baking box at 80-150 degrees C and then heating for 2-10 hours to obtain slow release microballoon, where the inlet temperature is 90-130 degrees C and the outlet temperature is 50-90 degrees C.