Abstract: The quality of carbon fiber (CF) reinforced polyvinylidene fluoride (PVDF) composites depends largely on the interfacial interaction between fiber and matrix. CF was modified by dopamine (DA) through a simple dip-coating method after removing the epoxy sizing agent on CF surface. The functional groups and roughness of CF surface were investigated by atomic force microscopy(AFM), X-ray photoelectron spectroscopy (XPS)and Fourier transform infrared spectroscopy (FT-IR). Results showed that epoxy sizing agent was removed and a polydopamine (PDA) layer was formed on CF surface. Afterwards, the virgin CF(VCF), removing epoxy sizing agent CF (RCF), the PDA functionalized VCF (DAVCF) and the PDA functionalized RCF (DARCF) were incorporated into PVDF or PVDF matrix modified by adding maleic anhydride (MAH) (PVDF-g-MAH) resins to prepare composites. The mechanical and interfacial properties of composites were investigated by scanning electron microscope(SEM), contact angle measurement, mechanical properties test. Results showed that after modification, the surface roughness was increased, and the interfacial bonding between DARCF and PVDF matrix was improved. Compared with PVDF/VCF, the bending strength and modulus of PVDF-g-MAH/DARCF were increased by 71.3% and 36.9% respectively, which indicated that the effects of dopamine and PVDF-g-MAH modification were positive on the interfacial bonding between fiber and matrix.