The invention discloses a reactive compensation control system and a reactive compensation control method based on fuzzy control. The reactive compensation control system comprises a fuzzification interface unit, a fuzzy inference machine unit and a defuzzification interface unit. The fuzzification interface unit obtains a fuzzy set and a membership degree table of voltage deviations and power factor deviations. The fuzzy inference machine unit obtains a fuzzy control regulation table and obtains a fuzzy relationship R between a fuzzy control relationship matrix A of the voltage deviation eu and a fuzzy control relationship matrix B of the power factor deviation ephi. The reactive compensation method comprises an initializing step, a capacitance inputting control step and a capacitance eliminating control step. A power factor is calculated and compared with a preset value. When the power factor is lower than the preset value, the fuzzy control module performs the capacitance inputting control step; and when the power factor is higher than the preset value, the fuzzy control module performs an electric eliminating control step. The reactive compensation control system and the reactive compensation control method have advantages of controlling a reactive power absorbed from the power grid side by a load within a certain range, and furthermore preventing oscillation caused by repeated switching of a capacitor set.