Embodiments of the invention disclose an automatic gain control method and apparatus for an audio signal. The method comprises the steps of determining a volume difference value between practical volume of the audio signal and a set volume threshold value; if the practical volume is determined to be in a range of smooth processing interval according to the volume difference value, calculating target volume according to the volume difference value; and adjusting the audio signal according to the target volume and outputting the adjusted audio signal. Through the technical scheme, automatic gain control on the volume of the audio signal is realized, and the continuity of volume range adjustment of the audio signal is effectively improved, so that the output audio signal is smoother and the usage experience of a user is improved.