As the core of automotive welding production line, the development speed and quality of automotive welding jig impact on the automobile production cycle and manufacturing precision directly. At present, the traditional design method of automotive welding jig is difficult to adapt to the developing speed of auto body. In order to improve the design efficiency of the welding jig, a rapid automobile welding jig design method based on parametric technology is developed in this paper. Supported by parametric theory, combining with CATIA secondary development approach, the principle and structure of the automobile welding jig rapid design system are presented, and related key technologies in rapid design system developing are studied deeply, and a rapid welding jig parametric design system is developed finally. Taking one station of rear side member for example, the generation process of automotive welding jig is analyzed in detail, and design practice shows: the welding jig designed by this system has shorter development cycle then the traditional method.