In the manufacturing of large-tonnage forging equipment, heavy and redundant of the body structure components always result in increased manufacturing costs, high energy consumption and performance degradation. Therefore, the lightweight design of machine body becomes one of the important goals in green design of modern forging equipment. Firstly, based on the static and dynamic FEA of YQK-1250 frame hydraulic press body structure, the rational shape optimization results were analyzed through ANSYS Workbench. The thicknesses of the six related ribs were determined as the lightweight targets. Then, a preliminary lightweight optimization is carried out with orthogonal experimental design which provided approximate ranges for the further APDL analysis. Finally the improved lightweight design is optimized by the aide of APDL efficiently. It is validated that the mass is reduced by 4.52% with less influents on the overall performance.