Data transmission method and system in wireless local-area network

The invention provides a data transmission method and system in a wireless local-area network and relates to the field of wireless communication and solves a problem that the prior transmission chance sharing mechanisms affect the data transmission efficiency. The method includes that a first station sends a wireless frame to a second station in an obtained transmission chance, wherein the wireless frame carries notification information for the second station to use the transmission chance to communicate with a third station. The technical scheme is applicable to transmission change management in a data relay process of the local-area network and realizes transmission change control right management under the control of the first station.