The application discloses a method and device for determining a DPD (Digital Pre-Distortion) coefficient, and a DPD processing system, which are used for improving a speed of calculating the DPD coefficient, so that the DPD coefficient can be timely updated to implement nonlinear compensation on a power amplifier, thereby improving signal quality. The method for determining the DPD coefficient, which is provided by the application, comprises the steps that: a FPGA (Field Programmable Gate Array) determines a forward matrix according to an input signal of the power amplifier, and determines a coefficient matrix according to a feedback signal of the power amplifier; the FPGA calculates an inverse matrix of an autocorrelation matrix of the coefficient matrix, and calculates a cross correlation matrix of the coefficient matrix and the forward matrix; and the FPGA determines the DPD coefficient according to the inverse matrix of the autocorrelation matrix of the coefficient matrix and the cross correlation matrix.