Abstract：Carbon fibers with different surface chemical structure were achieved by changing the oxidative intensities in the electrochemical anodic oxidation, and then these fibers were chosen as the reinforcements of carbon fiber/epoxy resin composites. Effect of surface chemical structure on the properties of composites was researched. The results show that surface activity increases greatly after electrochemical oxidation. The relative contents of oxygen and nitrogen increase from 3.10% and 1.12% to 13.07% and 5.96% respectively. When the current density is lower than 15A/m2, the higher the values of O/C and N/C, the better the interfacial bonding between carbon fiber surface and the epoxy resin. Among the oxygen-containing functional groups, -COOH is the key factor which can determine the chemical bonding between carbon fiber surface and the resin matrix.
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