The majority of mechanical parts worked under mixed lubrication conditions, especially for components worked under extreme conditions such as high speeds, heavy loads and surfaces with significant roughness. However, it’s difficult to deal with the problem of contact and lubrication at same time. Howeve the previous studies were under full-film condition and mostly with smooth surfaces. So the mixed lubrication is the weak point for the study of interface mechanics. The accurate system numerical method be used to solve the the unified model for mixed thermal elastic hydrodynamic lubrication(TEHL) . The result shows that the model was accuracy which can simulate the transition from Mixed to Full-Film Lubrication.