The whole-angle hemispherical resonator gyro ( HRG) is a typical rate integrating gyroscope with the advantages of high precision, high reliability, and long life. The system bandwidth of the whole-angle HRG closed-loop control circuit is studied. The working principle of the whole-angle HRG is analyzed. The input-output control circuit model and the disturbance-output control circuit model are established respectively. Two models are formulated and simulated by Simulink program simulation. The dynamic characteristics of two control circuits are discussed. Finally, the experiment of the whole-angle HRG is carried out. Simulation results show that when the input angular velocity exceeds 532. 8°/ s, the parameter output fluctuation caused by the disturbance signal reaches the maximum and remains constant, which corresponding to the bandwidth of the control circuit is 1. 48 Hz. The simulation and experiment results indicate that the low bandwidth of the whole-angle HRG control circuit can lead to the fluctuation of the ellipse parameters caused by the disturbance signal and deteriorates the control effect. In addition, the frequency of the disturbance signal is proportional to the input angular velocity. The fluctuation tends to be stable when the input angular velocity exceeds the angular velocity with respect to the cut-off frequency of the closed-loop control circuit. The research results in this paper provide a theoretical basis for the dynamic performance analysis of the whole-angle HRG.