Performance testing for digital sun sensor is very important during the R&D process of digital sun sensor. In order to shorten the development cycle of digital sun sensor, and improve the precision of testing, a new method of testing for digital sun sensor is proposed, and the new equipment which can apply to the system of performance testing is designed. The automatic test system used collimator to simulate real light source of solar and achieved performance testing for digital sun sensor by using the interface adapters and the data system of acquisition and process. The testing results show that the method and equipment can achieve the performance testing and improve the test of precision and efficiency.