The impact of bus stop on the dynamics of traffic flow is studied by a cellular automata model. Two types of bus stops, non-harbor shaped and harbor shaped, are considered. The properties of traffic flow are investigated by analyzing the fundamental diagram and the spatial-temporal diagram. The influences of bus ratio and length of bus stop are analyzed in detail. The simulation results show that the non-harbor shaped bus stop has more influence on the traffic flow, and the flux cannot be effectively increased by extending the bus stop length; the harbor shaped bus stop has less influence on the traffic flow and the flux can be improved by extending the bus stop length.