Abstract: An epoxy-based composite reinforced with carbon fibers (C/EP) was prepared by vacuum impregnation process.The specific surface area and tensile fracture load of carbon fibers were determined after anodic oxidation treatment,and the effects of fibers surface treatment on mechanical properties of C/EP composites were also discussed.The anodic oxidation resulted in the reduction of fibers tensile strength,the larger the current density and the longer the oxidation time,the more the loss.The specific surface area of carbon fibers increased with the oxidation time when the current density was 2A/m2 and initially increased then decreases at 1A/m2.The flexural and shear properties of the C/EP composites with properly oxidized fibers were greatly improved,while the impact strength falled to some extent.Its believed that the interface adhesion of the C/EP composite could be enhanced by the anodic oxidation treatment of carbon fibers,but the oxidation time should not exceed 2 minute in order to obtain a better general mechanical performance.