Most of the existing defect detectors focus on the size, location, depth and number of defects of the tested components. The instrument is usually large in size and requires high accuracy for the environment and motion devices. In contrast, the direct random bed motion, which aims at finding and locating defects, is highly efficient, low-cost and environmentally practical, while the research on vibration-resistant defect tester is rare.In order to solve this problem, based on the principle of micro-scattering imaging in dark field, a set of optical component surface defect detection device is built, and the influence factors of light intensity, illumination angle, wavelength and other defect detection factors are experimentally studied, in order to provide design basis for the follow-up development of on- line defect detection instrument. The experimental results show that the most important factor affecting the sensitivity is the azimuth angle and pitch angle of the incident light, which is more than 30 degrees between the incident light and the scratch direction. When the pitch angle is between 60 degrees and 70 degrees, the higher detection sensitivity can be obtained. In addition, improving the illumination intensity can help to improve the detection of defects. In the visible range, the wavelength has little effect on the sensitivity.