Affecting the normal running and determining the service lives of internal combustion engines, the lubrication and wear of the piston ring and cylinder liner pair are one of the most important area in tribology and studied both by theoretical analysis and experimental investigation by many researchers. In this paper, two-dimensional full numerical analysis is developed for the lubrication analysis of the piston ring based on the flow of lubricant. The forming of the lubricant film and the characteristics of the pressure distributions on the piston ring surface are studied. The detailed effects of many different factors, such as temperature, surface roughness, mixed lubrication and deformation of cylinder liner, are discussed. The calculating results show that the lubrication performance of piston ring significantly depends on those factors. This paper may provide some insights for the analysis of the lubrication performance of piston ring.