Objective: To prepare Sanzi cataplasm and optimize its formulation

then evaluate its in vitro release. Method: Based on single factor tests

taking overall desirability of quick stick power

shear strength and sensory evaluation as index

central composite design-response surface methodology was used to optimize matrix formulation of Sanzi cataplasm.In vitro release of Sanzi cataplasm was evaluated by using sinapine thiocyanate and rosmarinic acid as indexs. Result: Optimal formulation of Sanzi cataplasm was as follows:1.85 g of Viscomate NP-700

0.6 g of Plasdone K-90

0.13 g of dihydroxy aluminum

2 g of kaolin

0.08 g of tartaric acid

0.02 g of EDTA

10 g of glycerol

3.5 g of Sanzi extract.Sanzi cataplasm had suitable adhesion

no sticking residue

good paste character and skin adhesion.Average contents of sinapine thiocyanate and rosmarinic acid were 0.748

0.282 mg·cm-2

respectively.In vitro release of sinapine thiocyanate and rosmarinic acid were zero-order kinetics

their release rates were 37.91

14.30 μg·cm-2·h-1

respectively. Conclusion: This optimized formulation of Sanzi cataplasm is reasonable with good paste property and release performance.