The invention provides a dispatch data transmitting method, an AP (access point) and a system. According to the method, the AP is enabled to select one client from a currently-accessed client list as the dispatch client, a corresponding transmission window is assigned for the client, the situation that only one client transmits upstream data at the same moment is guaranteed, and the problem of hidden node is well solved. According to the embodiment of the invention, the AP is allowed to flexibly adjust the transmission window assigned for the client according to actual situations such as the state of the client.