Residence time of buses at bay stations is the main factor of influencing efficiencies of bus stations.In order to rationally design bus stations,taking bay stations at mid-blocks as a case study,with queuing theory and kinematics principles,an estimated model of residence time of buses at bay stations in different situations is established,and a calculation method of residence time is also given.The simulation results show that the average time of bus getting in station is slightly larger than that of exiting due to relative position at one platform.Compared to the number of passengers getting on or off buses,arrival rate of buses has more evident influence to residence time.For one bus waiting for getting in one station,its residence time increases with the increase of arrival rate,and time gap between two kinds of situations (the bus need to wait for a while to exit the station,or not) becomes smaller.This model provides effective reference to plan and design bus stations and improves efficiency of bus systems.