Transdermal drug delivery has become one of the research focuses in pharmaceutical formulations due to its potential advantages. In order to overcome the natural barrier function of the skin, several physical, chemical and pharmaceutical enhancement strategies have been developed to promote the transdermal permeation and adsorption of drugs. Electret is a kind of functional dielectric material with permanent electric polarization state. The electrostatic filed and micro-current produced by electret can be used as physical permeation enhancer to improve the transdermal drug delivery. In this article, we reviewed the mechanism, influencing factors and current research progress of electret as one of the physical enhancing permeation strategies.