In order to give full play to the advantages of distribution network edge computing and improve the level of fine operation and management of distribution network, aiming at the problems of rough calculation of distribution network open capacity, relying on manual experience and not effectively using data enabling decision-making, a distribution network open capacity calculation and opti-mization decision-making method of distribution network expansion based on distribution network edge division is proposed. Firstly, considering the seasonal and daily load characteristics, the dis-tribution network edge feeder division and the common variable open capacity are calculated based on the depth-first traversal method, which includes seasonal and daily time series characteristics. Secondly, considering multiple objectives such as the matching of open capacity and load curve, load balancing, and three-phase balance of station area, the optimal decision model of service ex-pansion and installation is established, and the refined load optimal access scheme is obtained at two levels from feeder area to station area. Finally, an IEEE standard power distribution system and a real power distribution network are used to verify the efficiency of the proposed open capacity calculation method. The proposed service expansion decision method can effectively apply the open capacity analysis results to obtain a refined load access scheme that takes into account multiple objectives.