The present invention relates to the field of communications technologies and discloses a data processing method and apparatus to obtain a DPD non-linear distortion compensation coefficient under a QPSK mode. The embodiments of the present invention receive a first data flow, and perform interpolation into the first data flow to obtain a second data flow; receive a third data flow, and calculate a data flow signal quality difference between the third data flow and the second data flow; and obtain a DPD non-linear distortion compensation coefficient according to the data flow signal quality difference and the third data flow or the second data flow. The embodiments of the present invention are applicable to the scenarios of obtaining a DPD non-linear distortion compensation coefficient in QPSK mode.