A mute processing method used in a multi-person communication system is provided. The method is capable of automatically sending mute frames when there are no sound inputs from terminals of the multi-person communication system. The method includes the steps of: collecting input signals from a microphone; obtaining a maximum amplitude of the input signals within a present time span; sending a mute frame if each maximum amplitude of the input signals within each of previous continuous time spans is less than a predetermined amplitude and the maximum amplitude of the input signals within the present time span is still less than the predetermined amplitude, otherwise, coding the input signals within the present time span; and outputting the mute frame or coded signals. A related apparatus is also provided.