Abstract: A digital closed-loop drive control circuit was designed based on digital signal processing(DSP) to improve the stability of the drive signal of double H quartz tuning fork gyroscope, and the frequency tracking algorithm of drive signal was proposed. Considering that the vibration amplitude of the drive tuning fork had a minimal impact with the frequency change, a phase control loop was used to track drive mode resonant frequency, and a pair of quadrature reference signal generated from Hilbert transformer were used to detect phase. Experiments have shown that the phase standard deviation of proposed frequency tracking algorithm is 4 mrad and the frequency tracking accuracy is up to 0.003 4 Hz when the double H quartz tuning fork gyroscope is in stable operation.