Among common three-phase phase-locked loops (PLLs), the dual second-order generalized integrator based PLL (DSOGI-PLL) has good comprehensive performance, but there are still some shortcomings in DSOGI-PLL. In this paper, an improved DSOGI-PLL based on frequency-locked loop feedforward is proposed. The addition of frequency-locked loop can accelerate the dynamic response of DSOGI-PLL. Besides, a digital realization method of second-order system based on typical type-II IIR algorithm is used to optimize the programming and reduce the computational burden. Finally, the correctness and practical effectiveness of the proposed method are verified by simulation analysis and experiments.