Abstract: Starch-g-MAH-St(SMS), prepared by the solid state reaction method, is the graft copolymer of corn starch, maleic anhydride (MAH) and styrene (St ). SMS/styrene-butadiene rubber (SBR) composite was prepared by mechanical blending. The mechanical properties, hot air aging properties, dynamic mechanical properties and micro morphology were investigated. The results show that the mechanical properties of SMS/SBR composite are superior to those of starch/SBR composite and vulcanized SBR. When the charging amounts of St and MAH are both 10 % of the weight of starch and the content of SMS is 20 g per 100 g SBR, SMS/SBR composite has the best mechanical properties. The tensile strength of composite is 10 MPa after hot air aging at 100℃for 48 h. The glass transition temperature ( T_g) of SMS/SBR composite is lower than that of vulcanized SBR. The micro morphology analysis shows that the size of starch particle is decreased, the dispersibility of starch is increased and the compatibility between starch and SBR is improved after modification.