An apparatus and method for compensating for data distortion caused by the phase slew of a frame reference signal in a User Equipment (UE) that accesses an asynchronous Wideband Code Division Multiple Access (WCDMA) communication system are provided. In the distortion compensating apparatus, an Finite Impulse Response (FIR) filter receives I channel data and Q channel data, each of the I and Q channel data having a plurality of chips, multiplies the I/Q channel data by a predetermined filtering coefficient, and outputs the product, in synchronization with the frame reference signal. A phase compensator compensates for an I-Q channel exchange occurring at an output end of the FIR filter when the phase of the frame reference signal is advanced or retarded.