Network data transmission method, device and system

The invention discloses a method for transmitting the network data, which comprises the following steps: A. a transmitting end decomposes each MAC short frame needing to be combined into a common part and a combination-needing part; B. a control part of a combined frame, which is used for instructing the information of the combined frame and location information of all the short frames, is generated according to the common part of the MAC short frames and the combination-needing part of each MAC short frame; C. the common part, the combination-needing part of each short frame and the control part of the combined frame are combined into a combined frame; D. the combined frame is sent out. The invention also discloses a device for transmitting the network data and a system thereof. In the invention, a plurality of short frames are combined into a long combined frame for transmission, thus increasing the network transmission rate. Besides, time threshold value and number threshold value of the short frame of the combined frame are introduced to control delay and dithering effectively.