The utility model discloses a phase-control reactive power dynamic compensator including a current sampling device, an isolating switch, a null line switch, a controller, a thyristor six-pulse phase-shift trigger, a compensation unit, a self-coupling transformer and a circuit breaker. The current sampling device, the controller, the thyristor six-pulse phase-shift trigger, the compensation unit, the circuit breaker and the isolating switch are sequentially connected together. An input terminal of the self-coupling transformer is connected with the compensation unit. An output terminal of the self-coupling transformer is connected with the null line switch. The phase-control reactive power dynamic compensator provided by the utility model controls conduction angles and conduction time of a thyristor through measuring power grid current of a load connecting point in real time, so as to control magnitude and phase of current flowing through an electric reactor. Continuous reactive power adjustment is realized, so that stable and quick dynamic reactive power compensation is realized.