The automatic design optimization of mechanical structure requires a strong framework to integrate CAD and CAE software. This paper presented an automatic structural design optimization framework through integrating SolidWorks, Patran, Nastran and Isight. To facilitate engineering applications, the framework encapsulated the process of modeling and analysis, therefore, designer’s repeated work was not required and design productivity was greatly boosted. The principle of the framework was illustrated. The involving secondary development of SolidWorks and Patran was demonstrated, respectively. The exchange of model and data among software was explained. At last, a case study of sensitivity analysis and two-objective design optimization for a wallboard was explained, which validated the feasibility and practicality of the design optimization framework.