Objective To optimize the particle size of Huoxue powder by contents comparison of emodin,phellodendrine,berberine and jatrorrhizine before and after permeabilized skin absorption of Huoxue powder in different particle size of 0.150,0.075,0.048,0.038 mm.Methods The contents of emodin,phellodendrine,berberine and jatrorrhizine in transparent absorbent fluid of Huoxue power in different particle size within 24 hours were measured by ultra performance liquid chromatography tandem mass spectrometry,and optimize its particle size by contents comparison of the effective components.Results The contents of the active components in Huoxue power with the particle size of 0.075 mm were high before and after percutaneous absorption.Conclusion Particle size of 0.075 mm is best for Huoxue powder.