The model of ultra-heavy vibrating screen has been established by using finite element analysis software ANSYS, the stress distribution of the screen box has been revealed under static load, meanwhile, analyses dynamic characteristics of the screen box structure for ultra-heavy vibrating screen, then, has gotten the low order natural frequency and vibration mode of the screen box, and the stress distributions and deformation in various parts of the screen box under rated load, which provided a necessary basis for the design improvement and dynamic strength study about the screen box. In allusion to the cracks of the bottom screen frame and side panels, according to the stress analysis conclusion, improve the screen box structure and change the original welding connection of the bottom screen shelf steel pipe with the side panels into flange, and this improvement gets good results in the field.