A data transmission system is provided for improving transmission scope and efficiency. The system includes a data device having a device identifier; a server having a server-side of an application program; and a mobile terminal having a client-side of the application program. The data device receives a trigger instruction, and broadcasts within a preset distance the device identifier of the data device according to the trigger instruction. When a distance between the mobile terminal and the data device is less than or equal to the preset distance, the mobile terminal enters the application program to receive the device identifier broadcasted by the data device, uploads the device identifier to the server-side of the application program, receives web page information that is corresponding to the device identifier and obtained by the server-side according to the device identifier, and displays the web page information on the application program of the mobile terminal.