As an important part of the automobile assembly, automobile frame bears the complex loads from the road and loaded, and be installed car assembly as the carrier, and thus the frame strength and stiffness in the car overall played a very important role in the design. This article use Solid Works to design a frame of a truck, and focus on using the finite element analysis software ANSYS study mechanical analysis and study of the vehicle frame. Here discussed the pure bending conditions and reverse the conditions of static strength, the static stiffness analysis. The analysis showed that the frame of the stress value is less than the ultimate strength of materials to meet the design requirements, but the intensity is too large, so the economy is relatively poor, while considering the local strength of the frame. According to this characteristic of the truck frame, this paper presents a program on the frame lightweight design, the results of optimization makes the weight of frame to reduce, saving raw materials, lowering production costs, improving fuel economy .