NOVELTY - Preparing hydrochloric acid sinomenine cataplasm comprises e.g. taking coarse caulis sinomenii powder, wetting using hydrochloric acid, filling into a percolation barrel, adding hydrochloric acid, covering hydrochloric acid surface by medicine powder, soaking, percolating, terminating percolating to obtain percolated liquid, adding lime milk to percolated liquid, adjusting the pH, filtering, adding hydrochloric acid to the filtrate to adjust the pH, extracting using chloroform, combining the chloroform layer, washing with water to neutralize, adding absolute sodium sulfate, and dehydrating.    USE - The method is useful for preparing hydrochloric acid sinomenine cataplasm.    ADVANTAGE - The method is simple, safe, reliable and ecofriendly, do not contain heating process, easily processes the mother liquor, and produces high yield.    DETAILED DESCRIPTION - Preparing hydrochloric acid sinomenine cataplasm comprises (i) taking coarse caulis sinomenii powder (100-1000 parts), wetting using 0.1-1 mol/l hydrochloric acid (60-1000 parts) for 0.5-8 hours, filling into a percolation barrel, adding 0.1-1 mol/l hydrochloric acid, covering 0.1-1 mol/l hydrochloric acid surface by medicine powder up to 2 cm, soaking for 6-48 hours, percolating at a speed of 2-6 ml/minute for 6-24 hours, terminating percolating to obtain the percolated liquid, adding lime milk to the percolated liquid, adjusting the pH to 10.5-12, filtering, adding hydrochloric acid to the filtrate to adjust the pH to 7-9.5, extracting for 2-5 times using chloroform, combining the chloroform layer, washing with water to neutralize, adding absolute sodium sulfate (3-6%), dehydrating, vacuum extracting, concentrating, and recycling chloroform, adding 6 mol/l hydrochloric acid to the concentrate, adjusting the pH to 2-4, stirring until the floated solid is dispersed, freezing, filtering, removing the filtrate, and drying the filter cake at 60-70 degrees C to obtain a coarse hydrochloric acid sinomenine, taking coarse hydrochloric acid sinomenine (5-10 parts), heating and refluxing through 10-95% ethanol or purified water (30-120 parts), completely dissolving, adding activated carbon (4%), thermal insulating and refluxing for 10-30 minutes, filtering in hot, concentrating the filtrate, cooling, separating crystal, filtering, cleaning the filtrate using 95% ethanol to obtain the hydrochloric acid sinomenine; (ii) weighing (in parts by wt.) hydrochloric acid sinomenine (1-4), sodium polyacrylate (NP700) (1-4), glycoside sucralox (0.1-0.4), tartaric acid (0.1-0.4), povidone K-30 (0.1-0.4), glycerol (15-30), kaolin (2-6), peppermint oil (0.2-0.6) and distilled water (30-70); (iii) taking sodium polyacrylate (NP700), polyvinylpyrrolidone (K-30), kaolin, glycoside sucralox and hydrochloric acid sinomenine, uniformly mixing, adding to the glycerol, and uniformly stirring to obtain a phase A, adding the peppermint oil and hydrochloric acid sinomenine to the distilled water to obtain a phase B, taking tartaric acid, and dissolving in distilled water to obtain a phase C, uniformly mixing the phase A with the phase B, slowly adding phase C, and stirring for 10-20 minutes to obtain a thick paste, uniformly coating the paste on the medical non-woven fabric, covering an anti-adhesion layer, placing at 25-28 degrees C with the humidity of 40-60% for more than 18-36 hours, and completely cross-linking the paste.