In this paper, a rigid-flexible coupling dynamic model is established for a certain type of excavator, the model is driven based on the measured cylinder displacement data and the dynamic simulation is carried out based on the measured displacement of the oil cylinder to drive the excavator, and the main performance parameters and the stress of the dangerous parts in typical working conditions are obtained. Based on the strength theory, dynamic simulation results and engineering experience, the crack prone parts of excavator boom and dipper are analyzed, and the typical high risk points of welding seam are obtained, which are verified by measured stress-strain data. Taking the hinge point load obtained from the rigidflexible coupling dynamics simulation as input, the fatigue life of the excavating boom and stick is predicted through the simulation of nCode fatigue analysis software. The results show that rigidflexible coupling dynamic simulation driven by measured data can accurately obtain the dynamic characteristics of excavator in the actual excavation process, and the method of extracting hinge load and predicting fatigue life based on the simulation model is feasible.