Abstract: OBJECTIVE To study the relationship between the indexs of the deformability of the different prescription of transfersomes containing coumarin-6 and transdermal permeation properties in vitro. METHODS Four kinds of different prescription of transfersomes containing coumarin-6 were prepared by using film dispersion method. The formulation was evaluated through vesicle size， vesicle size distribution， drug entrapment efficiency， deformability and rat skin permeation amount in vitro. The deformability of vesicles was measured with extrusion method and evaluated by such three different indexes as the deformation index D，the corrected deformation index D_cor and the index RD. RESULTS The evaluation index D and D_cor shows that the order of the deformability of four different prescription of transfersomes containing coumarin-6 is sodium deoxycholate（TF-SDC）>sodium cholate（TF-SC）>the blank (Liposome)>span 80(TF-SP80) and the evaluation index RD shows that the deformability order is TF-SP80>TF-SDC>TF-SC>Liposome; the order of cumulative penetration amount of coumarin-6 in 12h is TF-SDC>TF-SC>Liposome>TF-SP80. CONCLUSION The evaluation index D and D_cor have the best correlation with the cumulative penetration amount of coumarin-6 in vitro among 3 kinds of deformability index.