The invention provides a power flow calculation method for a complex topology active distribution network containing a direct current system in allusion to a problem of poor convergence in the AC-DC system hybrid power flow calculation process of the existing distribution network. The method is characterized in that the active distribution network is divided into a direct current system and an alternating current system according to a voltage source converter; whether weak loop running exists in the system or not is determined according to opening-closing conditions at a loop closing point so as to perform corresponding power flow calculation; and a power flow calculation result of the active distribution network hybrid system is acquired finally by combining a power flow calculation result of the direct current system. Corresponding adjustment is performed on the power flow calculation sequence of the direct current system and the alternating current system and selection for power flow calculation parameters of the converter under different control strategies of the grid-connected converter, and power flow calculation for the whole hybrid system can be realized by performing only one time of alternative iteration convergence on the direct current system and the alternating current system.