Abstract: To achieve a better interfacial adhesion between the fiber and matrix in composites, the continuous carbon fiber bundle was separated to the single fiber tape by the self-made air comb, then modified by the polyphenol film, which was electropolymerized by a cyclic voltammogram technique. The IR spectrum indicates that the polyphenol film formed on the carbon fiber surface with amounts of active agents such as hydroxyl and ether group can enhance the interfacial adhesion between the carbon fiber and the epoxy resin of the composites. Compared with the epoxy resin composites reinforced by the carbon fiber without surface modification, the strength of transverse tension, longitudinal tension, and interlaminar shear of the epoxy resin composites reinforced by the carbon fiber tape modified with polyphenol film are improved by 90%, 45% and 110%, respectively. The experimental results also show that the carbon tape can increase the mechanical properties of the composites, much better than the carbon fiber bundle.