The invention discloses a reactive voltage partitioning method comprising the following steps: inputting basic parameters; determining the number of voltage pilot nodes; determining the number M of partitions through reactive voltage sensitivity calculating and characteristic value sorting; selecting voltage pilot nodes, and calculating an objective function by use of a greedy algorithm; carrying out reactive voltage partitioning, and getting a partitioning scheme by use of a C-mean clustering algorithm; and carrying out reactive power reserve verification and sensitivity index verification, readjusting partitions for each node with reactive power reserve below a lower limit, setting the nodes with higher reactive voltage sensitivity parameters Sij as key load nodes, and taking appropriate measures to improve reactive voltage control for the key load nodes. A grid can be divided into a plurality of regional sub grids according to the reactive power balance characteristics. Through pilot node judging, determining and selecting, the nodes can be divided into multiple groups according to the reactive power regional balance characteristics of the nodes. The degree of electrical coupling between the nodes in each group is different, and thus, reactive voltage can be adjusted.