Abstract: The optimal dispatch problem of flexible interconnected AC/DC distribution systems is studied. By introducing flexible interconnected devices combining soft open point（SOP） and DC charging devices at the boundary of the distribution network, an improved multi-regional and multi-objective distributed optimization model of flexible interconnected distribution systems is established, which takes into account various distributed resources. Through the establishment of boundary and SOP decoupling models, the system optimization is divided into several sub-problems, including microgrid sub-region optimization, distribution network sub-region optimization, microgrid and distribution network partition boundary optimization, and flexible interconnected device optimization. For protecting the privacy of each region, the dispatch scheme in which each region, partition boundary and SOP participate in distributed optimization is proposed. Furthermore, the adaptive step size adjustment mechanism for the alternating direction method of multipliers is adopted to improve the computing efficiency. Finally, the effectiveness and expansibility of the algorithm and the economy of the flexible interconnected model are verified by simulation.