As the research object, the mobile robot chassis is designed. Firstly, the mobile robot chassis intensity design is processed in accordance with the chassis external load. According to the design results, the structure model is constructed in ANSYS, the strength and stiffness is checked and its structural dynamics characteristic is computed. Then, based on the numerical value analysis, the non-sensitive variable of the bodywork is analyzed and the optimization model of the body structure is established. The result of the Numerical Optimization proved that, the inherent structure frequency characteristics did not change significantly in the case of the body weight components reduced. The mobile robot platform is set up in the laboratory, the experimental results showed that the robot chassis design is reasonable, in line with the requirements of mobile robots.