The invention discloses a data transmission method, device and system. The method comprises the steps that a transceiver detects whether received first attribute information is updated or not, wherein the first attribute information is the attribute information of a playing device; transmitting the first attribute information to an adapter when it is detected that the first attribute information is updated, and controlling the adapter to generate a closed signal; and reading the first attribute information stored in the adapter when an output device detects the closed signal. According to the method, the device and the system, the technical problem in the prior art the output information of the output device mismatches the playing device due to the fact that EDID (Extended Display Identification Data) information is solidified in the VGA-to-HDMI adapter is solved.