In order to improve the efficiency of car body structure concept design, Concept car body structure design system was developed on UG/NX5 platform, the system realized CAD modeling and CAE analysis with fully parameter design method, and it created car body template by parametric design tool such as Child rule and Attribute. The interior and external database of car body was built by EXCEL and parameters in database were read and write by Spreadsheet. Name parameter, Design parameter, Rule parameter and Description parameter were designed in the system and CAD/CAE model were driven to implemented related design function by the these parameters. Finally, feasibility and reliability of the system was verified by calculating bending stiffness and torsion stiffness of a car body.