EPDM rubbers were prepared and the effect of lignin as coupling agent was investigated by means of mechanical and thermal properties. As a contrast, using vinyl triethoxy silane (VTS) coupling agent in EPDM rubber was also studied. The median diameter and the specific surface area of lignin used were 6.61 mu m and 722.24 m(2) kg(-1), respectively. Properties of EPDM rubbers were assessed by tensile testing, thermogravimetric analysis (TG/DTG) and scanning electron microscopy (SEM). The results showed that using lignin coupling agent, the mechanical properties were better than that of pure and adding VTS' EPDM rubbers. Thermal analysis revealed that containing lignin rubber had better thermal stability. SEM results indicated that the inter-phase cohesion between the lignin molecule and EPDM particles was enhanced.