Provided is a Digital Pre-Distortion (DPD) apparatus and method for processing a signal that is input to a power amplifier in a wireless communication system. The DPD apparatus includes a DPD unit configured to pre-distort an input signal that is input to the power amplifier, using DPD information; and a signal processor configured to capture signals for estimation of the DPD information from each of an input terminal and an output terminal of the power amplifier, detect peak signals of the captured signals, separate the detected peak signals into a plurality of intervals depending on a power level, separately store the detected peak signals, estimate the DPD information using the peak signals stored for each interval, and provide the estimated DPD information to the DPD unit.