In-chain multi-functionalized random butadiene-styrene copolymer possessing definite dimethylamino groups along the polymer backbone, poly(butadiene-co-styrene-co-1,1-bis(4-dimethylaminophenyl)ethylene) (poly(Bd-co-St-co-BDADPE)), has been designed and synthesized via living anionic copolymerization of excess BDADPE with butadiene and styrene in benzene at 50 A degrees C, using sec-butyllithium as initiator. The incorporation of BDADPE unit results in increases both in glass transition temperature and thermal decomposition temperature of the terpolymers. Such multiple dimethylamino groups along the rubber backbone effectively improve the dispersity of carbon black (CB) in the corresponding composites, as verified by scanning electronic microscopy observation. Also the tensile strength, elongation at break and the value of dynamic loss coefficient at 0 A degrees C of the CB/poly(Bd-co-St-co-BDADPE) vulcanized composites, are significantly enhanced. This in-chain multi-functionalization of matrix rubber via anionic copolymerization employing BDADPE as copolymerizable monomer, provides a facile and effective method to prepare CB-based rubber composites with improved tensile strength and elongation at break, as well as good wet skid resistance.