In this article, a cationic acrylic resin and an epoxy resin which have certain surface tensions were prepared. The two resins were blended together, and after electrodeposition, a complex paint film can be obtained which is designed to comprise a couple of layers. The results of Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy showed that a layer-separation structure can be built in the paint film. The upper layer is mainly of acrylic resin, and the lower, chiefly of epoxy resin. Studies on the surface tension showed that the surface tensions of the component resins were the driving force of layer separation. Also, the greater the disparity of the two resins＇ surface tensions, the more striking the extent of the layer separation of the complex structure.