The detection result of the traditional current detection method based on the instantaneous reactive power theory will produce large errorSwhen the power grid voltage is asymmetry、harmonic distortion、frequency discontinuity. According to the Ip-Iq current detection theory, a current detecting method of the positive and negative sequence decoupling network based on the complex filtering was proposed. The operation principle was analyzed, the mathematical models were built, and the current detecting network structure was designed. Because the proposed PLL used the positive and negative sequence decoupling network based on the complex filtering, this method can track the positive phase sequence of the fundamental wave under the complex power grid conditions. Meanwhile, because the current filtering also used the positive and negative sequence decoupling network based on the complex filtering, the current after filtering can separate the positive and negative sequence more accurate. Simulation is done to validate the current detection network under the conditions that the power grid voltage is asymmetry、harmonic distortion、frequency discontinuity. The results show the feasibilitySandSeffectiveness of this method.