An object-oriented modeling method was proposed to develop a simulation software package named GVDS which could be used to predict some aspects of dynamic behavior of railway vehicle. The package based on multi-body dynamics mainly consists of three parts, an interactive pre-processor, the solver and an interactive post-processor. With UML, demands and structure of the software package are represented. By modeling of the geometry and behavior of each object, virtual prototype of railway vehicle is formed and by the simulation, the critical speed of hunting stability, wheel-rail contact forces and so on can be determined and the hunting stability, curving behavior and ride comfort can be analyzed and evaluated. Finally, some cases are simulated. The simulation results show the effectiveness of the proposed method.