Construction of nice vehicle dispatching service system is the key of urban intelligence modern transportation management. The three-tier architecture and the development platform of the system are introduced in the paper. The key technologies of implementation are discussed in detail. In key technologies, real-time signal is decoded by using control of serial communication in order to implement real-time position and optimization of classical Dijkstra algorithm is realized in the paper. System can obtain all kinds of information about vehicle rapidly and provide the effective service for the vehicle management and development.