A new method to calculate the electrical distance is proposed， which fully consider the role of network structure and various sources of reactive power. According to the relationship between voltage perturbation and weight matrix to, each node in the system will be mapped to a n-dimensional space, then construct a new electrical distance between nodes. With regard to the instability reactive power and voltage control network partitioning features, this article proposed multigroup improved FCM as voltage control partitioning algorithm and applied to the IEEE 30-bus and 118-bus system. At last, the partitioning result is analyzed in detail and compared with the other algorithm to show the accuracy and feasibility of the proposed algorithm.