Abstract: The analyses of elastohydrodynamic lubrication of crankshaft bearings were carried out considering the deformation of engine block for the main bearings of a four-stroke four-cylinder internal combustion engine. The lubrication of crankshaft bearing was analyzed by kinetics method. The deformation of bearing surface under pressure of oil film was calculated by deformation matrix method. Comparison on with and without considering the deformation of engine block, the journal orbit, maximum film pressure, minimum film thickness, end flow-rate and journal frictional coefficient of bearings showed little variation nearly in one engine working cycle. Only in a certain peroid of one engine working cycle, the maximum film pressures of bearings decreased slightly while the minimum film thicknesses of bearings increased slightly. Therefore, the effect of elastic deformation of bearing surface under film pressure can be excluded in a lubrication analysis of engine main bearing when a high calculation accuracy is not required.