Payload racks on space stations usually suffer micro-vibrations due to a variety of disturbances, such as cabin device operation, attitude and orbit control, activities of astronauts, etc.Thus microgravity vibration isolation system is needed to fulfill the requirements of many acceleration sensitive experiments.The paper proposes a method to improve the performance of the vibration isolation system by designing a decoupled configuration of the system.Such configuration presents new placements of the actuators, which is based on the parallel mechanism theory.