Data transmission method and system in wireless fidelity network

The invention discloses a data transmission method in a WiFi network, which comprises the following step: when data transmission is carried out, sending data information comprising identity authentication information to a corresponding terminal user according to a WiFi network confirmed by the identity authentication information. Meantime, the invention also discloses a data transmission system in the WiFi network. The method and system of the invention can effectively avoid collision in the WiFi network, and can solve the problem of avoiding data collision depending on increasing interframe space in the working process of a CSMA/CA protocol, thereby improving the interactive efficiency between a network side and a user terminal.