Abstract: The second phase of the manned space flight project will develop manned space labs for a series of space scientific experiments. Vibration isolation system is indispensable for both International Space Station and Shenzhou spaceship to satisfy the requirement of scientific experiments. In this paper, the passive vibration isolation system for the space scientific experimental rack in manned space shuttle has been studied and designed. According to the actual mounting, the vibration isolation system layout is designed. As a rigid body, a 6-degree of freedom dynamic model of the scientific experimental rack is developed, a 3D model of experimental rack and vibration isolation system is created in ADAMS, and system performance in time domain and frequency domain are obtained. The system parameters are optimized to improve isolation performance.