Due to the special working principle, and the effect caused by fabrication technology and assemble error on the precision and performance of hemispherical resonant gyro(HRG), a suitable control circuit is needed to revise and compensate these nonideal characteristics, the currently used control circuit was limited to improve the precision of gyro, the stability of zero bias can only receive 0.07（°） /h. This paper detailed the work principle of HRG under forcetorebalance mode and designed a digital control circuit based on proportion integrate differential(PID) technology, introduced the PID algorithm,detailed analysis of HRG error source and the digital control loop. Testing result shows that this digital control circuit can improve the accuracy and the zero bias stability of HRG effectively. Compared with the intrinsic control circuit, the precision was improved by an order of magnitude at 0.005 （°） /h.