Abstract: Traditional approaches to optimize the operation of the urban bus network rely on surveys, which are expensive, time-consuming, inaccurate and with limited spatial coverage of lines and areas. In this paper, we analyze the operation state of bus networks for two typical zones in Shenzhen based on bus GPS data and ST-Matching method. Percolation theory is applied to find the bottlenecks in the bus network. The pinpointed bottlenecks are different from the most congested road segments. Therefore, this paper provides a method to improve a whole bus network operation efficiency in a highly efficient and lower cost way.