SBS embedded with micro dispersed crumb rubber modified asphalt was prepared by degraded crumb rubber by twin screw extrusion at high temperature. The effect of degradation degree, type of rubber source, content and crosslinking process on the structure and properties of SBS modified asphalt was investigated. The results show that the degraded rubber is easily dispersed into SBS modified asphalt in micro size. The incorporation of degraded rubber increases the ductility at low temperature and enhences the aging resistance. In the same time, the handling viscosity of SBS modified asphalt is not notably increased by the addition of degraded rubber. The hot storage stability of asphalt modified by SBS embedded with rubber can be realized by crosslinking technology.