Abstract: The application of geographic information system （GIS） in urban public traffic systems,greatly improves people’s life efficiency,simplify the management of urban public transport system. Using GIS methods such as buffer analysis and overlay analysis, local optimization of a single bus line for a complete complex urban bus network. It can also be used for overall planning and optimization of a simple urban bus network that has not been fully developed. Using Azimuth coding to relate the code of bus code with the general running routes. The bus number are the specific codes of bus in different routes, its perfect function is to display the general framework of the bus route. Setting up a new method of encoding and optimizing the bus routes,the result showed that the application of GIS in urban public traffic systems, The significance of public transport coding mode is convenient for people to make simple choices when taking public transportation,handy some institution to manage the public transport,reduces the error rate to a certain extent when people choose the bus, and improves the overall bus efficiency. The adjustment and optimization of bus route and bus network can increase the operation efficiency of public transportation system and promote economic efficiency.

Key words: geographic information system （GIS）, route optimization, network analysis, coding optimization