Based on the operation characteristics of doubly-fed wind generation system under non-ideal grid voltage conditions, this paper studies the influence of the grid harmonic on the doubly-fed induction generation’s output characteristics. It also analyses the different consequences of the DFIG output power and electromagnetic torque under typical harmonic conditions. On this basis, the PR control strategy under ideal grid voltage conditions is improved and completed, and a PR control strategy is proposed which targets to eliminate the effects of harmonic on the output characteristics of DFIG wind generation system. In order to verify the correctness of the control strategy, simulation studies on a 1.5 MW doubly-fed wind generation system prove that the improved control strategy can efficiently smooth the instantaneous output power fluctuation and electromagnetic torque pulsation.