Abstract: OBJECTIVE To prepare the patch of Angelica dahurica coumarins and investigate its transdermal absorption characteristics in vitro. The foumula was chosen to improve the drug's permeation rate. METHODS Angelica dahurica coumarins was dispersed in pressure sensitive adhersive(PSA). A monolithic drug-in-adhesive transdermal patch was developed using sialorrhea technology. The experiment of percutaneous penetration of anthony pig skin in vitro was operated by Franz diffusion cells. HPLC was used to determine drug's content and permeation rate. The influence of some factors on the transdermal flux were investigated, such as the kind and the content of penetration enhancer, the kind and the content of PSA, technological parameter of the content of angelica dahurica coumarins. RESULTS The best formulation were Angelica dahurica coumarins 1.0 mg·cm^-2, Eudragit E100 9 mg·cm^-2, oleic acid 0.6 mg·cm^-2 and curing time 40 min. The permeation rate reached 0.82 μg·cm^-2·h^-1. CONCLUSION The drug-in adhesive patch of Angelica dahurica coumarins have high transdermal rate and good physico-characteristic. The optimized formula and technology is stable and feasible.