Piezoelectric resonators, usually working at a resonant state with stable amplitude, are the core components of resonant sensors and actuators. As an approach to research the piezoelectric resonator driving circuit, a dual closed-loop control circuit is used to realize the resonant frequency tracking and the amplitude stabilizing through phase-locked loop (PLL) and automatic gain control (AGC). By optimizing the parameters of each component in the dual closed loop circuit, the piezoelectric resonator can work stably at the resonant frequency. The results of the open-loop experiment and the closed-loop experiment show that the dual closed-loop circuit can lock the resonator phase at 59°, and the error is less than 3°. The amplitude of output signal is controlled at 12.8V, and the error is less than 0.2V. The experimental results show that the circuit is capable of stabilizing the amplitude of the resonator output signal and tracking the resonant frequency of the resonator.