Abstract: AIM　To investigate the transdermal delivery mechanisms of the flexible nano-liposomes, conventional nano-liposomes and lecithin-cholate mixed micelles through mouse skin. METHODS　Liposomes and micelles were applied onto the mouse skin non-occlusively in vitro and in vivo, then the drug concentrations in the skin, receiver and blood were determined. RESULTS　In vitro permeation studies showed that flexible nano-liposomes and mixed micelles transported measurable amount of cyclosporin A through the skin. Conventional liposomes precluded drugs permeate through the skin while deposited it in the skin. In vivo studies indicated that blood concentration reached peak value at 8 h after the application of flexible nano-liposomes. Both conventional nano-liposomes and mixed micelles failed to deliver measurable amount of drug into the blood. CONCLUSION　Liposomes fuse with the skin. Flexible nano-liposomes penetrate through the skin under the pressure of hydration force. Mixed micelles promote transfer in state of solution.