The Urban Public Transportation Information Service System, for the bus arrival time showed on the intelligent electronic station board, is designed to provide accurate and timely information which can help travelers choose transit lines and the shortest paths, can improve the travel efficiency and attract more potential travelers. However, the current bus arrival time prediction model under application can't achieve satisfactory results. This paper analyzes the technology components of the bus arrival time, and builds real-time dynamic models for each component. Finally, it adds up all the technology components of the bus arrival time, gets a much more accurate prediction model.