Abstract: Finite elements mode and experimental mode of 4105 diesel engine crankshaft were analyzed respectively in order to get the vibration characteristics of 4105 engine crankshaft and verify the correctness of finite element model. The corresponding vibration frequencies and models were obtained. The inner product correlation degrees between the two kinds of model were calculated and the vibration mode were compared. The results showed that the inner products correlation degree between the calculated mode and the experimental mode was a high correlation, with coefficient of 0.7, which verified the effectiveness of the finite element model. The comparison between the finite element mode and the experimental mode showed that the maximum deformation mostly occurred at the end of the crankshaft. The research on mode correlation confirmed the natural vibration characteristics of crankshaft, and can provide a reference for crankshaft design optimization and vibration reduction by crankshaft finite element.