In order to improve the quality of semi-trailer tanker design, shorter the development cycle, lower cost, and combine with structural features of its own semi-trailer tanker, the use of modular design theory, a module partition, structural analysis and interface settings and other methods of semi- trailer to the overall structure of tanker design the general framework of semi-trailer tanker. With the UG/OPEN and Microsoft C++6.0 development tools, parameterize the parts of semi-trailer tanker. Developed in the context of the semi-trailer tanker UG rapid design system design module, and verify its feasibility.