A functional styrene-butadiene copolymer is disclosed. More specifically, the copolymer is prepared by radical polymerization of a styrene monomer, a butadiene monomer and an epoxy acrylate monomer in an emulsion state and ring-opening of the resultant styrene-butadiene-epoxy acrylate copolymer. When blended with silica, the disclosed copolymer provides excellent wet stopping performance and superior wear resistance. Therefore, it can be usefully applied for industrial materials including fuel-efficient tires, snow tires, belts, hoses, etc.