Taking the rolling mill oil film bearing as the research object,the oilwater twophase flow of elastohydrodynamic lubrication model was established with transient and thermal effect of the Reynolds equation.The lubrication transient behaviors of the rolling mill oil film bearing after water contamination of lubricating oil,and the effect of initial conditions on lubrication transient behaviors were analyzed.The results show that the pressure and thickness of the lubricating film is changed significantly under different instant.With the increasing of water content,the viscosity of the lubricating oil is increased,the center pressure and the center film thickness of the lubricating film are increased,the minimum film thickness is firstly increased then reduced,the maximum temperature is reduced.With the increasing of initial rotational speed,the maximum pressure is decreased,the inlet zone pressure,the secondary pressure peak and the film thickness are increased.With the increasing of initial rolling force,the maximum pressure is increased,the inlet zone pressure,the secondary pressure peak and the film thickness are reduced.