A method and apparatus for decoding a parametric-encoded audio signal are provided. According to the present invention, parameters extracted from a bitstream of a parametric encoded audio signal are adjusted by a user and component signals are synthesized based on the adjusted parameters to be displayed to a user so that a user can adjust the amplitudes of the component signals to apply various sound effects according to the user's desire. In addition, since an equalizer function is embodied in a codec of an audio reproduction apparatus, additional equalizer modules are not required and thus complexity of the audio reproduction apparatus can be reduced.