Abstract: Oxybutynin hydrochlorid(oxb) ethosomes were prepared by ethonal infusion and homogenization. Orthogonal method was used to optimize the formulation of the ethosomes preparation.The average size and size distribution were determined by dynamic light scattering,and the shape of ethosomes was observed by the scanning electron microscopy.In vitro transdermal flux of oxb through the separated rat skin was determined by Franz-type diffusion cells. The encapsulation efficiency of the ethosomes was ( 48.1±1.4)％，and the average size was (98±12 )nm，when the ethosomal preparation consisted of 3% egg phospholipids,45% ethanol and 5% oxb.Transdermal flux of oxybutynin hydrochloride in various preparations at 24 h was ranked in the order of: ethosomes(oxb 5%)＞unencapsulate-oxb-free ethosomes (oxb 2.4%)＞physical mixture(oxb 5%)＞ethanol solution(oxb 5%)＞45％ethanol solution(oxb 5%).The results suggested that ethosomes could be the ideal carrier in oxb transdermal delivery.