The present invention discloses a transmit power control method and system, and a sending apparatus. The method includes the following steps: acquiring first information that is used to adjust transmit power for sending a first signal; acquiring power of each working channel; and determining a to-be-adjusted working channel according to an adjustment step, the first information, and the power of each working channel, so as to adjust the transmit power for sending the first signal. According to the foregoing manner, the present invention can adjust transmit power for sending a first signal, avoid saturation of an automatic transmit power control apparatus, and save energy.