Abstract: The distributed power source connected to the flexible interconnected distribution network is characteristic of randomness and relevance,bringing great challenges to the research on the power supply capacity of the distribution network. In this paper,considering the correlation of distributed power sources, the Nataf transformation and third-order polynomial transformation are used as correlation processing methods;the maximum load supply capacity is used as the power supply capacity evaluation model; the three-point estimation method,repeated power flow method combined with AC-DC alternating iterative algorithm is used as a probabilistic evaluation method for the power supply capability of flexible interconnected distribution networks. In the IEEE33 calculation example,the three-terminal SOP is used to construct a flexible interconnected distribution network for method verification,which verifies the effectiveness of the proposed algorithm. In addition,it is concluded that the power supply capacity of the system can be improved by adjusting the reactive power of SOP and the control parameters of the AC side voltage amplitude.