The invention discloses a three-phase power flow correction method for a power distribution network containing distributed power sources. The method specifically comprises the following steps that a distributed power source three-phase model is constructed; a power distribution network three-phase system model containing the distributed power sources is established; nodes and branches in the power distribution network three-phase system model are numbered; three-phase load parameters of all the nodes in the power distribution network are stored according to the numbering sequence of the nodes, and three-phase impedance parameters of all the branches in the power distribution network are stored according to the numbering sequence of the branches; the three-phase load parameters of all the nodes and the three-phase impedance parameters of all the branches are subjected to per-unit treatment; problems existing in power flow calculation of the power distribution network containing the distributed power sources are analyzed, and the grid-connected voltage of the distributed power sources is corrected; convergence precision is selected, a power distribution network three-phase system containing the distributed power sources is subjected to three-phase forward-back substitution power flow calculation. According to the method, the characteristic that the output current and the grid-connected voltage of the distributed power source model are symmetric is considered, and a positive-sequence component of the network-side voltage is selected as the grid-connected voltage of the distributed power sources to participate in power flow calculation.