We analyze the shock wave refraction in a spatially developing shocked mixing layer by means of direct numerical simulation.Both regular and Math reflections can occur depending on the relative strength of the induced shock wave over the vorticity of interacting vortex in the mixing layer.The stronger incident shock wave frequently refracts Mach reflection.The shock polar diagram is used to determine the shock wave refraction pattes.Moreover,the vortices are deformed and compressed by the shock wave,and their vorticities are increased.The interaction of shock wave and coherent structure can be helpful to enhance the mixing process.