Abstract: The response behaviors of the interior of carbon fiber composites under the effects of electric-thermal load were very complicated for the composites had the characteristics of composition complexity, anisotropy and so on. In order to investigate the electric-thermal response of carbon fiber composites, self-devised electric-thermal damage test device was adopted, the temperature distribution on the surface of carbon fiber multifilament specimens under different current intensities was tested and the changing rules of the resistance of carbon fiber multifilament versus temperature were obtained firstly, and carbon fiber multifilament which had temperature-sensitive effect was preliminarily revealed. Then, the changing rules of tensile strength, elongation at break and tensile modulus under different current treatment conditions were investigated, and the morphology and microstructure changing of the materials before and after current treatment were analyzed by SEM and FTIR. The investigation results indicate that the heating effects of fibers in the galvanization promote the further solidification of the matrix, and improve the interfacial adhesion property of multifilament at the same time. However, when the current intensity is too high, the tensile strength of multifilament will decrease for the damage of fibers themselves or ablative degradation on matrix and interface layer, thus reduce the properties of carbon fiber composites.