NOVELTY - Preparing sinomenine hydrochloride cataplasm comprises extracting percolating liquid from 100-1000 parts by weight (pbw) of caulis sinomenii rough powder by 0.1-1 mole/l of hydrochloric acid (60-1000 parts by volume) for 0.5-8 hours, taking raw material including sinomenine hydrochloride, sodium polyacrylate (NP700), glycosides hydroxyl aluminum tartrate povidone K-30 and glycerol kaolin peppermint oil distilled water, and weighing the raw materials, uniformly mixing and adding mixture into glycerol, and uniformly stirring to obtain product.    USE - The method is useful for preparing sinomenine hydrochloride cataplasm.    ADVANTAGE - The method is capable of simply, effectively and economically preparing the sinomenine hydrochloride cataplasm with improved productivity and without toxicity in environmental-friendly manner.    DETAILED DESCRIPTION - Preparing sinomenine hydrochloride cataplasm comprises extracting percolating liquid from 100-1000 parts by weight (pbw) of caulis sinomenii rough powder by 0.1-1 mole/l of hydrochloric acid (60-1000 parts by volume) for 0.5-8 hours, filling in a percolating cylinder, further adding 0.1-1 mole/l of hydrochloric acid to cover the powder by a liquid level for 2 cm, sinking for 6-48 hours, percolating at 2-5 mol/minutes for 6-24 hours, sampling a processed cation exchange resin or 152-type resin on the percolating liquid with a diameterto-height ratio of 1:8-12 at 2-5 times of column volume/hours till there is precipitate, checking effluent by silicotungstic acid test solution, stop sampling after checking no alkaloid spot by thin-layer chromatography, washing the precipitate by purified water till the washing liquid having no color, sinking resin by ammonium solution (8-15%) and hydrochloric acid solution (3-10%) for 12 hours, washing the precipitate by ammonia water-ethanol solution with pH of 8-11, or washing the precipitate with 152-type resin by 3-10% of hydrochloric acid at 2-5 BV/h, receiving the checking precipitate in the washing solution by silicotungstic acid test solution, if no precipitate is present in the washing solution then stop receiving the checking precipitate, combining the washing solution, neutralizing the solution by hydrochloric acid or ammonia water till pH is 6-8, removing salt, concentrating and drying, obtaining sinomenine hydrochloride rough product, taking 5-10 pbw of sinomenine hydrochloride rough product, heating and back flowing by 30-120 parts by volume of ethanol (10-95%) or purified water till completely dissolving, adding activated carbon (3-6%), keeping a temperature, back flowing for 10-30 minutes, filtering while hot, concentrating, cooling, crystallizing and filtering a filtrate, washing a filter cake by ethanol (75-95%) till the filtrate has no color, obtaining sinomenine hydrochloride, taking raw material including sinomenine hydrochloride sodium polyacrylate (NP700), glycosides hydroxyl aluminum tartrate povidone K-30 and glycerol kaolin peppermint oil distilled water, weighing sodium polyacrylate (NP700), povidone K-30, kaolin, glycosides hydroxyl aluminum and sinomenine hydrochloride, uniformly mixing, adding mixture into glycerol, uniformly stirring, obtaining an A phase, adding peppermint oil and sinomenine hydrochloride into distilled water, obtaining B phase, weighing tartaric acid, dissolving in distilled water, obtaining C phase, uniformly mixing A phase with B phase, slowly stirring, adding the C phase, stirring for 10-20 minutes, obtaining a thick paste, uniformly coating the paste on a medical non-woven cloth, covering the antiseize layer, laying at 25-28 degrees C at humidity of 40-60% for 18-36 hours, and completely cross-linking the paste.