Geodesic laser gyro is a kind of inertial sensing device based on the Sagnac effect to measure the angular velocity of the earths rotation, which can be used in the fields of world time and geodesy. Laser gyroscopes are generally controlled by piezoelectric ceramics to shift the mirror and improve frequency stability accuracy. In view of the influence of the normal displacement of the spherical mirror on the resonator during the operation of the frequency stabilizing mechanism, starting from the definition of ring cavity stability, a more realistic ray tracing simulation, which is different from the traditional optical matrix analysis of the resonator stability, is used to analyze the influence of the normal displacement of the spherical mirror on the light output stability of the resonator. The simulation results show that the size of the ring cavity is positively correlated with the normal displacement range of the spherical mirror. The displacement range measured by experiments is about 1. 492-1. 695 mm, and the error between the experimental and simulation results is within 1%. In this paper, the influence of normal displacement of spherical mirror on geodesic laser gyro during the operation of frequency stabilizing mechanism is studied. The research results have some reference significance for the frequency stabilizing control and gyroscope construction of geodesic laser gyro.