Abstract: In order to complete the testing of very high precision star sensor, a high precision static multi-star simulator which can achieve accurate simulation of star point was designed. The collimating optical system has wavelength range of 500-900 nm, at 20℃, the effective focal length of 150 mm, and distortion less than 0.02%, MTF reaches diffraction limit within the full filed of view of 7.2. For temperature changes from -45℃ to 65℃, used ZEMAX software to analyze athermal performance of the optical system, applied ANSYS software to complet finite element analysis of the mechanic structure. The results show that, athermal performance of the optical system is fine, shape change and deformation stress on mechanical structure are small, the anti-defocus performance of the simulator can meet the requirement of technique index. Calculate theoretical accuracy of the designed simulator and provided a group of measured data. Depends on the measurement results, the error of position for single star 3, the error of angular distance between stars 10, are both better than required calibration accuracy of the star sensor.