Abstract: The detection accuracy of the traditional phase-locked loop technology is disturbed by the direct current（ DC） component,negative sequence component and harmonic component when the three-phase grid voltage contains DC component, asymmetrical voltage and serious distortion, which makes it cannot track the frequency and phase of power grid voltage accurately. In order to solve the problems, this paper proposes a synchronization method which combines the sequence-decoupled resonant（ SDR） controller and cascaded double second order generalized integrator based software phase-locked loop（ CDSOGI-SPLL）. The SDR controller is used to separate positive and negative sequence components. The cascaded double second order generalized integrator（ CDSOGI） is used to carry out secondary separation and harmonic suppression, and to eliminate the effect of DC component on orthogonal signal of CDSOGI.The simulation and experimental results show that the grid voltage synchronization information can be accurately collected when the three-phase grid voltage contains DC component, asymmetrical voltage and serious distortion.