The system construction and working principle of the resonant optical gyroare introduced in this paper.At the same time,aiming at the problem thatthe induction of the white noise into the resonant optical gyro system affectsthe output accuracy,the crosscorrelationprinciple among the signals in the system is theoreticallyanalyzed;and the noise filtering method of the signals by using the digital lowpass filter is presented.Through the rotation test and zerobias stability test of the gyro system,it is found that the amplitude range of the rotational output signals reduced from 300 to 60. The output accuracy is increased from 265.29 (°)/h to 62.96 (°)/h by using the Allan variance to fit and calculate the zerobias stability test data.The results show that the output accuracy of the system is improved effectively.