The scattering of defects on the surface of the mirror directly affects the performance and accuracy of the optical testing system. The scattering of the surface defect of the mirror can be detected by the laser scattering microscope. In order to ensure the detection efficiency and precision of the whole system, the microlens lens, the size of the spot and the power spectrum response of CCD are designed in the design of the hardware system. secondly, the laser scattering microscopic imaging test system is programmed on the software system, which can use the stepping motor to scan the surface of the mirror, and control the image acquisition card to capture the image and display it visually; To obtain the scattering image of defects, it is necessary to study the laser scattering laws of various types of defects, and to select a reasonable microscopic imaging Scattering theory for a specific type of defects. focusing on the effects of different incident angles of light sources and scattered light at different angles of the same incident angle on the imaging quality of defects, and the relationship between laser irradiation and smear scattered light imaging in the spatial domain is obtained. A high-quality plaque scattering image lays a solid foundation.