The ring resonator is the central role of ring laser gyro (RLG). Based on the ray transport matrix theory of the ring resonator, the influence of the path length control mirror (PLCM) deformation on the resonator stability is analyzed numerically by solving the self-consistent equation. Furthermore, the influence of the PLCM structural parameters on its comprehensive performance is simulated with the aid of the finite element software Ansys and demonstrated in experiments. The experimental results exhibit great agreement with the simulation, showing that the resonator dynamic stability can be greatly enhanced by the PLCM structural optimization, without almost any impact on PLCM length compensating efficiency. And the optimized PLCM can meet the gyro requirements in the vibration environment of conventional airborne navigation system. This will be of great value for the optimization of the ring resonator for RLG, especially for miniature RLG.