Abstract: Astress analysis of a diesel engine crankshaft is made by FEM based on dynamics analysis to determine the position of the initial crack and its propagation direction. The stress intensity factors of the cracks at various depths are calculated using displacement method on a substructure model, thereby the expression for the geometry factor of a 16V240ZJB diesel engine crankshaft is obtained by curve fitting. This work can afford a theoretical foundation for the fatigue and reliability analyses of diesel engine crankshafts of the same or alike types.