Surface defects are important criteria for evaluating the surface quality of optical components，mainly including scratches and pitting. To accurately evaluate the surface quality of optical components，this paper proposes a detection and evaluation method based on machine vision. Based on the principle of dark field scattering imaging，an image acquisition system is built，and a defect recognition system is designed using digital image processing technology. A digital evaluation system based on quality inspection standards has been developed to detect surface defects of optical components. The experimental results show that the evaluation results of the detection method on the surface quality of optical components are consistent with the manual evaluation results，and the matching degree reaches 100%，which verifies the reliability of the method.