The invention discloses a reactive compensation system. The reactive compensation system comprises an LCL filter circuit, an IGBT bridge, a capacitor, a thyristor, a reactive compensation unit, a voltage and current detection circuit and a control system, wherein the LCL filter circuit, the IGBT bridge and the capacitor are sequentially connected with a power grid side; the thyristor and the reactive compensation unit are sequentially connected with the power grid side; the voltage and current detection circuit and the control system are sequentially connected with the power grid side; the two ends of the capacitor are connected with the IGBT bridge; the voltage and current detection circuit collects voltage signals and current signals of the power grid side and transmits the signals to the control system; the control system processes the received voltage signals and the received current signals and sends control signals to the thyristor and the IGBT bridge respectively according to the processing result. Reactive parameters can be automatically and continuously adjusted according to the collected voltage signals and the collected current signals, and reactive power compensation can be carried out rapidly and highly precisely.