A method for realizing network access via Wifi, characterized by comprising: when an access terminal sending a network access command, CMD_ONLINE, according to a Wifi Station mode to a wireless router, and judging that the access terminal cannot be accessed by a network, constructing, by the access terminal, an extended data frame in a Wifi Direct mode to distinguish from a data frame which is directly exchanged between the access terminal and an intermediate terminal, and sending valid data for accessing the network carried in the extended data frame to the intermediate terminal; enabling, by both the access terminal and the intermediate terminal, a Wifi Station mode and a Wifi Direct mode thereof respectively, and when receiving the extended data frame used for representing that the access terminal accesses the network, from the access terminal, the intermediate terminal extracting the valid data for accessing the network; carrying, by the intermediate terminal, the extracted valid data in an extended Wifi frame and sending the extended Wifi frame to a wireless router; parsing, by the wireless router, the extended Wifi frame, sending the valid data obtained through parsing to the network, and obtaining response data from the network; carrying, by the wireless router, the obtained response data in an extended Wifi response frame, and feeding back the extended Wifi response frame to the intermediate terminal; and after constructing the extended Wifi response frame as an extended response data frame, feeding back, by the intermediate terminal, the extended response data frame to the access terminal, and the access terminal parsing the extended response data frame to complete network access; wherein the intermediate terminal refers to terminal which communicates with the access terminal in the Wifi Direct mode and communicates with the wireless router in the Wifi Station mode to access the network. when an access terminal sending a network access command, CMD_ONLINE, according to a Wifi Station mode to a wireless router, and judging that the access terminal cannot be accessed by a network, constructing, by the access terminal, an extended data frame in a Wifi Direct mode to distinguish from a data frame which is directly exchanged between the access terminal and an intermediate terminal, and sending valid data for accessing the network carried in the extended data frame to the intermediate terminal; enabling, by both the access terminal and the intermediate terminal, a Wifi Station mode and a Wifi Direct mode thereof respectively, and when receiving the extended data frame used for representing that the access terminal accesses the network, from the access terminal, the intermediate terminal extracting the valid data for accessing the network; carrying, by the intermediate terminal, the extracted valid data in an extended Wifi frame and sending the extended Wifi frame to a wireless router; parsing, by the wireless router, the extended Wifi frame, sending the valid data obtained through parsing to the network, and obtaining response data from the network; carrying, by the wireless router, the obtained response data in an extended Wifi response frame, and feeding back the extended Wifi response frame to the intermediate terminal; and after constructing the extended Wifi response frame as an extended response data frame, feeding back, by the intermediate terminal, the extended response data frame to the access terminal, and the access terminal parsing the extended response data frame to complete network access; wherein the intermediate terminal refers to terminal which communicates with the access terminal in the Wifi Direct mode and communicates with the wireless router in the Wifi Station mode to access the network.