Abstract: The conception of wall slip of lubricants on solid  liquid interface is elucidated based on quasi  plastic solid performance of lubricants under elastohydrodynamic lubrication condition. A model for theoretically predicting elastohydrodynamic lubrication failure in line contact is established. The results indicate that the effect of applied load and slide  rolling ratio on  elastohydrodynamic performance is obvious and elastohydrodynamic films would lose load carrying capacitiy and break down under certain applied load and slide  rolling ratio. In comparison with conventional theoretical formulae, the present results are more conformable to experimental data.