In order to meet the demands of calibration on the ground for optical navigation sensor with high precision, a method is given to design precise star charts simulator based on the characteristics of conventional technique by combined the OLED light source with fiber-optic light guide technology. The general structure of star charts simulator is presented after the analysis of its design. The coupling efficiency between the OLED and fiber is improved by a rebuilding of the coupling structure between the optical fiber and the light source as well as the fiber holding plate. By optimizing the design of the self-focusing lens in coupling system and the detail design of filters in stellar magnitude simulation system, a precise control is achieved to 5~10 for the stars positional accuracy. It is found that the design for star charts simulator approaches the requirement for the calibration of precise optical navigation star sensor through the theoretical analysis and the measurements for the magnitude and the stars positional accuracy.