Abstract: In order to realize the performance evaluation of the boom structure of the working device of LW900K loader, through analysis of the load relationship at the hinge point of the working device of the loader, based on the peak load of the measured load, the working device attitude at the moment when the bucket rewinding is completed and the unloading moment are determined as the typical attitudes, and the finite element simulation analysis is carried out under the peak load. The solid unit is used to establish the finite element model of the moving arm structure, and the load constraints and displacement constraints are determined, so that the safety coefficients of the structural strength of the moving arm corresponding to the measured peak loads in the two typical attitudes are 1.55 and 2.31 respectively. The structural strength of this type of loading machine arm is affluent, and it can be optimized to a certain extent.