The invention discloses a regional power grid reactive voltage control method based on a support vector machine. Voltage values of main nodes of a regional power grid and power factors of the main nodes of the regional power grid are used as sample elements, corresponding action strategies are used as sample values, state classification is conducted on a certain number of historical data of the regional power grid and the action conditions of adjusting equipment after classification are recorded, learning training is conducted by using a one-to-one multi-classification mathematical model algorithm of the support vector machine, a reactive voltage control model is generated, the model is corrected in the control process according to the gradual learning idea. Thus, online real-time control over power grid reactive voltage is realized, and coordinate actions of adjusting equipment between transformer substations of the same subsystem is effectively realized.