In order to control the satellite with high precision and stability, a semi-physical simulation system for satellite attitude and orbit control was established by Chinese and French astronomical satellite. The simulation closed-loop of the fine guidance sensor electronic star map simulator used in the system was studied. Firstly, the fine guidance sensor was introduced into the control system as a high precision attitude measurement component, and the input information was provided by ground dynamics. Secondly , the high precision measuring sensors and high precision control actuators were introduced into the closed loop. Thirdly , the rough measuring sensors and rough control actuators were replaced by mathematical model. Finally, the real-time simulation verification system was composed of the control system, the satellite management unit, the payload computer and the satellite power system through the ground real-time system. The experimental results show that under the condition of semi-physical test, small open window conditions of fine guidance sensor can be achieved, y, z axis stability is reached 2?/10 s and 5?/100 s. The attitude measurement accuracy and attitude control stability can be improved by the fine guidance sensor. It meets the requirement of satellite with control stability of sub-angular second.