The invention relates to a system and a method for testing and verifying the ground precision of a sub-arc second star sensor, and belongs to the technical field of satellite attitude control. The method can test and verify the precision superior to 0.1'' under the ground static and dynamic conditions of the product, and solves the problem that the star sensor product is difficult to effectively test and verify the sub-arc-second precision through the test. The method is easy to implement and convenient to use, the test cost can be effectively saved, and human resources are liberated. According to the method, sub-arc second precision test and verification of a single probe can be realized; meanwhile, sub-arc-second precision can be tested and verified after multiple probes are fused, the method can adapt to various sub-arc-second precision product types, good application and popularization value is achieved, and the method is a very-high-precision star sensor precision testing and verification method which is practicable, low in implementation cost and convenient to use.