In single-phase photovoltaic grid-connected inverter based on the double closed-loop control strategy, the secondary voltage disturbances of DC bus will be generated, resulting in the triple harmonic of grid current ,and affecting electrical energy quality. In view of these problems, based on analyzing the causes of the secondary voltage disturbances of DC bus,an double closed-loop control strategy increasing cycle integrator before DC bus voltage sampling is proposed in the article. The strategy can remove the triple harmonic of grid current cased by the secondary voltage disturbances of DC bus,and then effectively suppress the effect on electrical energy quality. Simulation and experimental results are given to verify the rationality and effectiveness of the strategy.