Aiming the problems existing in product design and the shortcomings in present mechanical system prototyping and considering railway vehicle virtual prototyping as design object, the product design procedure is studied in detail thoroughly, which is from railway vehicle design automation to obtaining of virtual model, to extraction product analyzing model based on multi-body system, to mapping from multi-body analysis model to digital visualized mode, again to map to performance analyzing model, and finally to get the analyzing results to guide the design. The contents of this thesis are as follows:(1) Based on the summary of the research status of virtual prototyping and railway vehicle virtual prototyping and aiming to the problems existing in product design and the shortcomings in present mechanical system virtual prototyping, the idea in this thesis is presented.(2) System structure of railway vehicle virtual prototyping is studied. Centering on our own studies, design and analyses of railway vehicle product are studied, and the framework of railway vehicle virtual prototyping is established, and the the overall thought is given.(3) Design automation of railway vehicle virtual prototyping is studied. Considering the important components of ralway vehicle as objects, relative technologies of design automation are studied and general method is obtained to get the prototyping model efficiently.(4) Auto-extraction of railway vehicle model attributes consisting with the principle of multi-body dynamics is studied. To make the model more accurate, combining CAD with the multi-body analyzing data an integrative data model is established, and relative technologies are examined thoroughly.(5) Abstraction and defination of multi-body system model are given. On the basis of extracted model, the multi-body structure is abstracted, delivered and decomposed into geometry model and physical model, and is mapped finally into solved model which can be recongnized liablely by dynamic system.