To develop the detection ability of ultimate stars, and use more dark stars as referenced stars of deep space aircraft navigation, a catadioptric star sensor with a proved Cassegrain configuration with three pieces of emending lens optical system is designed. In this system, the proved Cassegrain configuration is used to reduce the spherical aberration and coma out of optical axis and bring the focus and large size of entrance pupil at the same time; emending lens close to the image plane is mainly eliminating the remaining aberrations of catoptric configuration, the telecentric image plane design among the emending configuration is also benefit to the irradiance unification in full of field and decrease the sensitivity of image sensor setting. This system has a 180 mm focal length and F-number is 2, view of field is 3°×3°, the effective pupil area is 5106 mm2, energy centroid aberration is smaller than 2.5 μm, lateral color is better than 3.5 μm among 450~800 nm spectrum, over 80% energy of spot in less than 3×3 pixel, and modulation transfer function (MTF) is approaching to diffraction limit. The inner baffles of reflected lens and outer two-group baffles are introduced, through modeling and analyzing the stray light of system in the Lighttools, the designed result shows that in the range of 2° to 40° incident angle of stray light, the point resource transmittance is between 10-6 to 10-4. These results can provide a good reference for further star sensors with deep space catadioptric configuration star sensor.