According to car body steel structure features of China general railway passenger cars, based on finite element analysis software ANSYS, parametric programming language APDL is used for modeling the railway passenger cars. At the same time, adopts Tcl/Tk as interface redevelopment tool to prepare user interface, realizes the transmission of parameters between ANSYS and Tcl/Tk. By adjusting the corresponding parameters, the geometry model of car body steel structure can be automatically generated, this greatly reduces the design cycle, improves the design efficiency and lays the foundation for finite element analysis.