Optimizing the operation mode of the flexible interconnection device in the distribution network can improve the power supply reliability, and reasonable configuration of flexible interconnection device requires comprehensive consideration of equipment investment economy, power supply reliability and operation economy. In this paper, the operation configuration of flexible interconnection device is studied. Based on the average loss reduction rate of power load under the expected fault set, the distribution of flexible interconnection device is optimized, the distribution point that has great influence on power supply reliability is selected. Then, multi-objective fuzzy optimization is adopted to optimize the capacity of flexible interconnection device, based on the established objective function of minimum load loss and minimum distribution network loss. The approach degree of fuzzy optimization is taken to evaluate the optimal solution of multi-objective function. Moreover, the deterministic constraints of AC/DC power flow balance, and the uncertainty constraints of branch safety current and node voltage considering the power fluctuation of load and distributed generation are also included. Finally, based on the improved IEEE 33 node distribution network model, the operation configuration scheme proposed in this paper is verified and analyzed.