Abstract: Static finite element model of DFH - 852 tract-type tractor frame is established in this paper. The accuracy of the model is verified through experiments in laboratory. The actual loads borne by the frame and strain responses of some important positions of the frame are measured by field experiments under drawing, bulldozing and crossing-obstacle operating modes. Stress distributions of the frame under the above three operating modes are analyzed when the measured loads are used as input of computation. The maximum stress positions of the frame under the different operating modes are found out. Reasons causing the tractor frame failure are discussed. Corresponding structure modification proposals are proposed. The preceding research results provide a basis for strength analysis and design of the tractor frame.