Abstract: Oil supply conditions for elastohydrodynamic lubrication(EHL) in elliptical contacts were investigated.The effects of the effective film thickness of the supplied oil layers on the starved central and minimum film thicknesses were analyzed.Furthermore,the relations among the central and minimum film thicknesses and the formation position of the lubricating film were investigated.The results show that,when the effective film thickness of the supplied oil layer is very small,the central and minimum film thicknesses are also very small,and the formation position of the lubricating film is very close to the Hertzian contact ellipse,this is the serious starved state.If the effective film thickness of the supplied oil layer reaches a certain value,the central and minimum film thicknesses increase very little,and the extra lubricant can hardly enter the contact gap,so the oil supply condition will reach a quasi-fully flooded state.Nevertheless,if the thickness of the supplied oil layer continues to increase,the starved region will disappear completely,the oil supply condition therefore will be the actual fully flooded or the over flooded state.