An audio volume control circuit includes a signal intensity calculating circuit for generating a first signal intensity value corresponding to a signal intensity corresponding to an audio channel data; a low-pass filter for filtering the first signal intensity to generate a second signal intensity value; an averaging unit for averaging the second signal intensity value and previous M−1 second signal intensity values to obtain a third signal intensity value, with M being a natural number greater than 1; a gain calculating circuit for obtaining an original gain value according to the third signal intensity value with reference to the adjustment condition; a buffer for temporarily storing the audio channel data; and an audio volume adjusting circuit for generating an adjustment gain value according to the original gain value to adjust the audio channel data stored in the buffer.