Abstract: Rubber/carbon composites were prepared by mixing multiwalled carbon nanotubes (MWCNTs), carbon black or a mixture of carbon black and MWCNTs with rubber by a laboratory tworoll mill. Results showed that MWCNTs could effectively improve elastic modulus, stress at a defined enlongation, abrasion resistance and electrical properties compared to the carbon black additive. However, the tensile strength, tear strength, strain to failure, viscosity and processing properties of the MWCNT based composites were rather poor. The properties of the composites with both MWCNTs and carbon black added were improved effectively by the formation a grapeclusterlike reinforcing structure. When the weight ratio of MWCNTs to carbon black was 1∶4, the tear strength (78.4kN/m), hardness (68) and abrasion loss (0.112cm3/km) of the rubber/MWCNTcarbon black composite were better than those of the rubber/carbon black composite and the strain to failure (470%) and viscosity (65Pa · s) were better than those of the rubber/MWCNT composite. The rubber/MWCNT composites had excellent dynamic mechanical properties and could be used in tyres with low roll hysteresis and fatigue loss resistance.