The invention relates to a star sensor fault simulation system, which comprises a star simulator, a triaxial rotary table, a star sensor, an floatation platform, a rotary table control module, a star simulator control module, an image acquisition and attitude calculating module and a fault analog control module; the star sensor can realize optical imaging, the star simulator can realize space star map simulation, the triaxial rotary table can realize the satellite attitude jitter simulation, the floatation platform can isolate the influence of the external shake on the star simulator, the image acquisition and attitude calculating module can realize the image acquisition and treatment and then calculate the satellite attitude, and the fault analog control module can realize the each module configuration, fault mode configuration and fault simulation flow control in a whole system. The system can realize the fault simulation of the star sensor, the star simulator can simulate the external environment of sky to realize to interfere the produced star sensor fault by the stray light, and the motion of the rotary table is controlled to realize the fault simulation of the star sensor by the satellite attitude jitter.