Micro-vibration of aerostatic bearing caused by surface roughness is analyzed.The frictional resistance coefficient influenced by surface roughness is discussed.The relation between the frictional resistance coefficient with relative surface roughness and Reynolds number is obtained.Simulation the distribution of the flow with three typical models of surface roughness such as square

semi-circular and triangular

the diagram of speed and pressure distribution of three models.Simulation shows that surface roughness would cause vortex flow

as a result cause the micro-vibration of aerostatic bearing system.The results are of practical significance for the research on the source of the micro-vibration of aerostatic bearing.