Abstract: Intensity of the moving arm of the loader is directly related to service life of an entire machine. This paper deals with the way of intensity analysis of the box-like moving arm by using the finite element, photoelastic experiments and measuring the whole machine. The above three obtained results correspond with each other. Simplifying the spacesymmetrical structure of the moving arm into a plane for analysis is reasonable. This research result has been used in designing a new type of moving arm.