Abstract: In order to solve problems of fluctuation of voltage and low power factor caused by imbalance of reactive power of power grid, a kind of reactive power control system based on magnetically controlled reactor was designed. The system uses multi-variable control strategy, and can accomplish regulation of power factor, reactive power as well as voltage of busbar by controlling output reactive power of magnetically controlled reactor. The experiment result proves that the multi-variable control strategy can be applied to target parameter control effectively, and achieves expectant effect.