Abstract: The traditional power flow methods aren’t appropriate to the electrical distribution systems with distributed generators（DG）.Therefore,a direct unbalanced three-phase power flow algorithm was presented in this paper.The proposed approach which was developed based on the path matrix,utilized the special topological structure of distribution systems and established the incident matrix of node voltages and injection currents.Based on the assumption that the positive-sequence voltage magnitudes of PV nodes are invariable,the relation of reactive power and compensation voltage for the PV nodes had been derived by the positive-sequence component and path matrix.As a result,a new approach handling PV nodes of DG had been proposed and could be integrated into the proposed power flow method.It needn’t introduce any additional active power at PV nodes and kept the positive-sequence voltage magnitudes on their scheduled values,considering that reactive power limits were not violated.The results of the 6-bus and the 69-bus test systems verified the validity and universality of the proposed methods.