In the process of strengthening design of the diesel engine,the unbalance inertia force of crankshaft will cause the increase of journal inclination,therefore,it is necessary to study the influence of balance ratio on crankshaft vibration and lubrication characteristics of main bearing and connecting rod bearing.Based on the average Reynolds equation considering lubrication oil filling rate,GreenwoodTripp asperity contact theory and balance rate calculation theory,and by considering the effect of surface roughness and elastic deformation,the effects of different balance rates on crankshaft lubrication and vibration characteristics were analyzed by taking 12V150 diesel engine as an example.It is found that the minimum oil film thickness of the main bearing and the connecting rod bearing is increased in most of the time in an engine cycle,and the maximum oil film pressure and friction power loss are decreased in most of the time,while the horizontal bending vibration and free end torsional vibration of main journal and connecting rod journal are decreased in most of the time.In the lubrication design and vibration control of crankshaft bearing of high power density diesel engine,the influence of crankshaft balance rate should be considered comprehensively.