The utility model discloses a vacuum shunting voltage-regulating reactive power compensator including a voltage sensor connected with a power grid, a current sensor and an isolating switch. The vacuum shunting voltage-regulating reactive power compensator also includes a controller, a relay, a vacuum arc-extinction voltage regulator, a circuit breaker, an electric reactor, a capacitor and a discharging coil. The current sensor and the voltage sensor are both connected with the controller. The controller, the relay, the vacuum arc-extinction voltage regulator, the circuit breaker and the isolating switch are sequentially connected together. The vacuum arc-extinction voltage regulator, the electric reactor and the capacitor are sequentially connected together in series. A series branch of the electric reactor and the capacitor are connected with the discharging coil in parallel. The vacuum shunting voltage-regulating reactive power compensator provided by the utility model is high in response speed, great in compensation series number, high in precision, small in switching current and dynamic in reactive power compensation. Besides, power supply of the capacitor is not interrupted in a compensation process. The vacuum shunting voltage-regulating reactive power compensator is long in service lifetime.