OBJECTIVE: To optimize the extraction process of Xiaozheng plaster, a traditional Chinese medicine. METHODS: Xiaozheng plaster was prepared by water extraction and alcohol precipitation method with stachydrine content in water and the yield of powdered extract as evaluation indexes. The orthogonal test was carried out to optimize the reasonable parameters of the extraction process. RESULTS: The optimal extraction process for the prescription was adding 12-fold of water and decocting for 90 minutes at each time for three times altogether with alcohol precipitation concentration at 45%. CONCLUSION: The extractive condition can be optimized through visual analysis and the preparation technology is feasible.