With the rapid development of flexible DC distribution technology, the flexible interconnection distribution network composed of a DC distribution network connected to an AC distribution network through a voltage source converter has become a current research hotspot, but so far for uncertain distributed generation there is no literature to study the probabilistic load flow calculation of the flexible interconnection distribution network with power access. In view of the current situation of lack of flexible interconnection distribution network probabilistic load flow research, the article carries out uncertainty research. After analyzing several conventional probabilistic load flow calculation methods, the three-point estimation method combined with the improved AC/DC alternating iteration algorithm is used as the algorithm for the realization of probabilistic load flow in flexible interconnection distribution network; using the Nataf transform method and Cholesky decomposition to process the correlation of uncertain non-normal input variables; taking the IEEE33 node distribution system and the first domestic five-terminal DC demonstration project-DC distribution center as an example to verify the effectiveness of the proposed algorithm.