Abstract: In order to measure the roughness parameters of metal and insulating surface, the oblique incidence roughness measurement system based on laser scattering was adopted. Using a semiconductor laser source, the scattering spot of roughness surface was photographed by complementary metal-oxide-semiconductor transistor industrial camera. The correspondence between the speckle characteristic parameters and roughness was then analyzed. According the theoretical and experimental study, the monotonic relation between the characteristic parameters and the roughness was verified. By using MATLAB to design graphical user interface, the function of one-key roughness measurement was realized. The results show that the system's structure is simple, and the error between the measurement result and stylus measurement result is less than 8% (the insulation surface is less than 5%), so the roughness of different materials can be measured. This result is helpful to the study of roughness measurement of object surface.