Aiming at the design problem of rotation and stop time of dual-axis rotary inertial navigation system (INS), the essence of automatically rotary compensation of navigation error is analyzed, the measurement equation between the rotation and stop time and modulation effect of device error is derived, the influence of the single error and random error of the inertial device are simulated and analyzed. The research shows that the faster the speed is, the shorter stop time is, the better modulation effect on errors of inertial devices is, and the optimal rotation time and stop time are given.