Abstract: The relationship between oil layer thickness on surface and supply time was established by conducting oil layer measurement experiments on an oil-air generator. Then, the effects of oil layer thickness on lubrication performance were investigated based on point-contact starved lubrication model and oil layer thickness decay model under different speeds, loads and surface roughness. The results show that the time to fully flooded condition was independent on operating conditions under oil-air condition. Oil supply time and oil supply interval for establishment of effective lubrication can be optimized.