An apparatus and a method thereof, processes a voice signal of a mobile terminal in a mobile communication system. The apparatus to process a received-voice signal received through a wireless channel in a mobile terminal includes a digital signal processing unit to generate an encoded packet and frame type information defining a characteristic of the encoded packet by performing voice encoding on an audible signal input from a microphone. The apparatus also includes a received-voice controlling unit to determine a noise level in consideration of the frame type information and a level of the audible signal, and to control at least one of a tone and a volume of a received voice by the determined noise level.