In order to study the influence of stress distribution of the crankshaft system on the crankshaft design and reliability,the crankshaft system of a six inline cylinder engine was researched,the finite element model was established by finite element analysis software,and the coupling relationship of crankshaftbearing was established by EHD.Combined with dynamics,tribology,modal reduction method,dynamic response of the crankshaft and stress was analyzed.The stress,torsion angle analysis of the crankshaft under different load characteristics was compared based on different speed.The results show that with the decrease of load,the torsional angle is decreased,and it happens at later time.The stress caused by torsion is greater than that caused by bending for the second,the third and the fourth crankpin at different crank angle.The maximum stress of the sixth crankpin at the breakout pressure caused by bending is greater than that caused by torsion,but the fluctuation of the stress caused by torsion is larger than that caused by bending.When the shaft gap is decreased,the torsion angle is increased,the stress caused by torsion is increased.