To analyze the effect of main bearingjournal profiles on lubrication performance based on whole engine block,the Reynolds fluid lubrication equation and Greenwood-Tripp micropeak contact theory were used to establish the elastically hydrodynamic lubrication model of main bearing based on the flexible whole engine block.Considering the effect of journal misalignment and elastic deformation,the influence of main bearing and journal profile on bearing lubrication performance was studied by simulation.The results show that compared with the no profile and only considering the journal profile,the minimum oil film thickness of the main bearing considering main bearing and journal profiles increases significantly,the peak oil film pressure decreases,and the average friction loss decreases.When both the main bearing profile and journal profile are considered,within the scope of this study,with the increase of crankshaft misalignment angle,the minimum oil film thickness of the main bearing decreases,the peak oil film pressure increases,the average friction loss decreases.When the speed increases,the minimum oil film thickness of the main bearing increases,the peak oil film pressure decreases,the average friction loss increases.Therefore,the two factors of journal misalignment and working speed should be considered in the design of main bearing and journal profiles.