Abstract: The soft open point (SOP) can achieve flexible interconnection in the distribution network. However, the bidirectional flow of fault current makes existing fault location methods inapplicable. This paper proposes a SOP-based active control method for fault location in the distribution network to address this issue. The phase-to-phase fault type can be determined by detecting the voltage drop at the SOP port. For the two-phase short-circuit fault, the negative sequence current suppression control strategy is implemented, and the feeder terminal unit (FTU) collects the negative sequence current information. The fault section can be identified in the master station based on the differences in negative sequence current measured by each FTU. For the three-phase short-circuit fault, the control strategy of active injection of the characteristic signal is implemented, and FTU collects the characteristic current information. The fault section can be identified in the master station based on differences in characteristic current measured by each FTU. This proposed method does not require additional configuration of directional elements. It is compatible with existing feeder automation systems, thereby improving the accuracy of fault section location in flexible interconnected power distribution networks. Finally, based on the PSCAD/EMTDC simulation platform, the correctness and feasibility of the new method are verified.