A wireless transmission device capable of transmitting media from different channels concurrently. The transmitter of the device places the inputted TV signals and an audio/video signal on different segments of a frequency spectrum, combines the signals of all segments into one combined signal, and transmits the combined signal as a radio frequency signal so as to transmit signals from different channels at the same time. Meanwhile, a controller in the receiver of the device selects a needed channel signal from the received radio frequency signal according to a selection signal. Therefore with one A/V transmitter and multiple A/V receivers, multiple-channel media transmission and multiple-channel media reception is achieved.