In the process of the traffic accidents confirmation, the identification of vehicle speed when accident occurred is often an important basis for accident confirmation. The paper firstly discusses the models of mechanics and solving method for the vehicle front face, rear end, sides face ,slanted side collision based on the theory of collision mechanics ,it describes how to identify the vehicle rate and collision angle based on the model simplification, the theoretical analysis for dealing with the complicated accidents. The common and formulas are studied based on the classical collision mechanics method. The application range, parameters involved in selection and influence of the formulas are analyzed in detail. Finally the program based on C# is developed according to the identified calculation process for vehicle speed of traffic accident. The vehicle speed is obtained by selecting the collision type, entering the relevant accident pattern, inputting the parameters and clicking the command button .The application can store, modify and display results conveniently , improve efficiency on vehicle speed identification effectively and reduce the processing cycle of traffic accident availably.