Abstract: Four kinds of carbon fiber(CCF300, T700, CCF800 and CCM40J)/epoxy (CF/EP) composites modified by graphene oxide (GO) were fabricated using mould pressing. The effects of CF surface properties on GO-CF/EP composites were studied by means of micro-structures and dynamic thermomechanical properties. The results show that EP with GO significantly improves the wettability and the interfacial adhesion between the CF and the EP matrix. Micro-morphologies express that the destruction of the CF/EP composites mainly occurs at the interfaces between CF and EP matrix. However, the presence of GO makes the GO-CF/EP composites destructive form transits from interfacial debonding between CF and EP matrix to the interlaminar GO/EP region of the composites. The surface oxygen-carbon atomic ratio and grooves of the CF affect the glass transition temperature (T_g) of the CF/EP and GO-CF/EP composites significantly. The GO-CCF300/EP composite has the highest T_g because of its highest oxygen-carbon ratio. However, the GO-CCM40J/EP and GO-CCF300/EP composites exhibit better modification effect on T_g for more surface grooves.