Flexible interconnection of distribution networks can achieve dynamic capacity expansion of transformers，which is an effective way to improve the power quality of new distribution networks.This paper proposes a method for selecting interconnection points based on the minimum power moment，which comprehensively considers the source load state and its complementary relationship in the distribution network，obtaining the optimal interconnection point in the corresponding state.The location of the optimal interconnection point for the quasi full life cycle is obtained by employing the difference in load rates of interconnection lines during different periods throughout the year as the weight coefficient.Based on the proposed interconnection node，a method for calculating the injection current at the interconnection point with minimum system loss is proposed.Then，by considering line loss，transformer loss，and inverter loss，and taking the minimal total loss of the interconnected system as the objective function，the injection current at the interconnection point is obtained in the condition of satisfying the constraints of interconnection power balance and distribution network capacity，thus obtaining the interconnection power.Finally，the results are applied to practical cases.The study shows that the proposed method achieves a smaller total loss in the interconnection of two actual distribution networks than traditional head end interconnection methods.