Abstract: A new ground simulation systems is proposed to simulate the spatial microgravity environment. The system combines the machine transmission, motor driving in the upright direction and air-bearing in the level plane to simulate three-dimension spatial microgravity, in which the force of the executive device is reduced and transmitted by ball screws and guide poles, and the target gravity is counteracted by the force feedback control. Considering the friction and non-linearity of Permanent Magnet Synchronous Motor (PMSM) together with some outside disturbances, the inside loop uses a sliding model controller, and the outside loop uses a fuzzy CMAC neural network with rapid learning ability to compensate for the disturbance and uncertainty to assure the real time operation. The simulation result shows that the system is easily operative with light weight and high precision in the three-dimension spatial microgravity simulation.