Abstract: Focusing problems in urban CBD (Central Business District) area like disequilibrium passenger flow, lack of public transit resources and various troubles when getting on board…etc, this paper introduces a public transit dynamic query and pedestrian guidance system from standpoint of pedestrian.The authors firstly analyze the character of public transit passenger flow, as well as the shortages of several most popular existing public transit query software in China, and then raise the basic needs and fundamental requirements.Moreover, the overall functions and structure are discussed.Also, a modified Dijkstra algorithm and dynamic programming ideas are used as the essential algorithm, by which the system can work out different recommended bus-taking suggestions during different traffic conditions.At last, a method to realize this system is revealed.