In order to solve the problem that it is difficult to obtain the load spectrum of the bucket hinge of the hydraulic excavator in actual digging process, which leads to the difficulty of analyzing the bucket fatigue life,a bucket fatigue life analysis method was put forward based on common digging trajectory.The common digging tracks were selected from the actual digging process, and the digging forces of the hydraulic cylinders in each section of the common digging tracks were calculated separately, and the digging resistance load spectrum was obtained. Based on the digging trajectory, the excavation process of the working device was simulated, and the bucket hinge point load spectrum was obtained.Finally, the bucket finite element model was established, and the bucket statics and fatigue life were analyzed by combining the digging resistance and the hinge point load spectrum. Taking the bucket of 21T excavator as an example, its fatigue life was analyzed by using the above method, and the minimum fatigue life of bucket in J3J4 trajectory was calculated to be 3.293 6×107. The feasibility of this method is verified, which provides reference for fatigue analysis of working device of excavator.