Micro vibration of the aerostatic guide way has a significant impact on its dynamic characteristics and stability, which limits the development of pneumatic component. High pressure gas molecules collide with the supporting surface and the internal surface of the throttle during the flow process. Variable impulse of the surfaces aside for the gas film are affected by the changes of impulse which formed irregular impact force in horizontal and vertical direction. Microvibration takes place based on the natural frequency of the system and its frequency doubling. The vibration model was established to describe the dynamic characteristics of the gas film. By comparing computational results and experimental data, formation mechanism of the micro vibration in the gas film was confirmed. The result shows that the micro vibration of gas film can be produced no matter whether there is a gas chamber or not in the throttle. Meanwhile, The micro vibration of the guide way with air chamber is greater than that without any chamber under the same conditions. The frequency points of the vibration peaks are almost the same, as well as the vibration pattern in the frequency domain.