The surface characteristics of RS and MS carbon fibers were analyzed by using the scanning electron microscopy,specific surface area and pore volume test equipment. The interface properties of C/ C composite were tested by carbon push down method, bend strength and impact shear strength. The results show that the section of RS -Cf is circular and MS-Cf is kidney. The surface groove of RS-Cf fiber is clear, but obviously less than MS-Cf. The Special surface area and pore volume of MS-Cf are more than RS-Cf. The interface strength of MS-C/ C composite is higher than that of RS-C/ C composite,because the interface strength, bend strength and impact shear strength of MS -C/ C composite are 3. 80 MPa,65. 0 MPa and 35. 2 MPa respectively,being higher than RS-C/ C composite’ 2. 98 MPa, 55. 9 MPa and 32. 0 MPa.