In order to explore the influence of crankshaft offset technology on lubrication performance of main bearing during the strengthening process of diesel engine,considering the influence of diesel engine system dynamics,elastic vibration of moving parts and dynamic lubrication,the elastohydrodynamic lubrication model of crankshaft bearing system of 12V150 diesel engine was established.The lubrication performance of the fourth main bearing with different offset combinations and different offset distances was studied.It is found that the axis offset at the fourth spindle neck is large and the lubrication performance is poor.With the increase of the offset distance,the minimum oil film thickness of the main bearing is increased significantly,and the maximum oil film pressure is decreased significantly.When the left cylinder is biased alone,the peak oil film pressure is significantly improved,and the minimum oil film thickness is significantly increased when the two cylinders are offset simultaneously than that when the single cylinder is offset.