Based on reactive voltage sensitivity of the power network, this paper proposes a new method about reactive power voltage control partitioning, which bases on vector similarity theory. Firstly, general Tellegen's theorem is used to calculate the reactive voltage sensitivity of each node corresponding to other nodes, and the reactive power voltage sensitivity matrix is formed. Secondly, mathematical methods of vector similarity are used to calculate similarity among columns of the matrix, and a new electric range is defined to form electrical distance matrix. Lastly, fuzzy similar matrix is established and fuzzy clustering theory is used to divide voltage control regions. IEEE-30 system and IEEE-118 system show that the method of partition is accuracy and reasonable.