Transmission power control method and system, and transmission device

Disclosed are a transmission power control method and system, and a transmission device. The method comprises the following steps: acquiring first information which is used for adjusting the transmission power for transmitting a first signal; acquiring a power of each working channel; and determining a working channel, which needs to be adjusted, according to an adjustment step length, the first information, and the power of each working channel, so as to adjust the transmission power for sending the first signal. By means of the method, the present invention can achieve the adjustment of the transmission power for transmitting the first signal, and avoid the saturation of an automatic transmission power control device, thus saving energy.