Abstract: In this paper, the blending technology and the formulation of polyurethane asphalt elashic water proof coating were investigated in order to improve the strength and the elasticity of asphalt coating. By pre polymer mixing, a kind of polyurethane asphalt coating with high strength and good elasticity and excellent water proof properties was obtained. Compared with asphalts, the tensile strength and the fracture elongation rate of the coating obtained increase 10~15 times respectively, and the coating has advatages such as light weight, seamless, easy to maintain and to apply.