Abstract: The Hexapod micro-vibration system contains some self-contradictory technical specifications:the heavy load and the small order of vibration magnitude. In view of this fact, an automatic leveling pneumatic support system is designed for precisely unloading the dead weight and for the small order control of the actuators. The system consists of the four-point trapezoidal resilient mounting system with air springs when the system is in the work state, and the three-point stiff auxiliary mounting system for load support when the system is not in the work state. The automatic leveling control system has two features:the force coupling between the resilient mounting and the stiff mounting, and the non-linearity and the time-delay of the pneumatic control. To solve these two problems, an switch on-off control scheme including the continuous inflation and the pulse inflation is proposed. The experiment results show that the Hexapod system with a load of 200 kg can be automatically leveled within 140 s, and the displacement errors of the Hexapod's six actuators are less than or equal to 1 mm.