Objective: To optimize the extraction process of Xiao'er Wenli Zhixie plaster by supercritical CO2 fluid extraction technology and its matrix prescription.Method: Extracting amount of cinnamaldehyde was selected as the indictor

L9(34) orthogonal test was used to optimize supercritical CO2 fluid extraction technology of Xiao'er Wenli Zhixie plaster.Initial viscosity

peel strength and cohesive strength were selected as indictors

L9(34) orthogonal test was used to optimize matrix prescription.The uniformity of Xiao'er Wenli Zhixie plaster was investigated by the uniformity test.Result: Optimum extraction parameters were as follows:extraction temperature at 45℃

extraction pressure of 50 MPa

extraction time of 2.5 h

flow rate of CO2 of 20 kg·h-1.Optimum matrix prescription was as follow:polyvinyl alcohol-sodium polyacrylate-glycerol-carboxy methyl cellulose sodium (0.6:2.5:1.0:1.0).This prescription showed satisfactory performance of initial viscosity

peel strength and cohesive strength;its uniformity was 15

which was in line with regulation in the 2015 edition of Chinese Pharmacopoeia.Conclusion: The optimized extraction process is stable and available.The optimum matrix prescription of is simple and stable

which can be applied to industrial production of Xiao'er Wenli Zhixie plaster.