根据光阑衍射理论，以光阑衍射损耗灵敏度为参量，研究和分析了激光陀螺环形谐振腔的抗失调能力。基于激光陀螺的限模条件，为获得谐振腔的最佳光阑衍射损耗灵敏度，计算得到了激光陀螺抑制比下限。通过数值计算，研究了谐振腔增益和反射镜总损耗对其抑制比下限的影响，并得到了实验验证。研究结果表明：腔内增益越大，陀螺抑制比下限值越大；反射镜总损耗越大，陀螺抑制比下限值越小。这对激光陀螺环形谐振腔装调过程中抑制比的优化控制具有重要指导意义。

By means of the diffraction loss sensitivity of the diaphragm, the anti-alignment capability of ring laser gyro (RLG) is analyzed numerically. Deriving from the condition of mode suppression of RLG, the lower limit of mode suppression ratio (MSR), which is defined as the ratio of the loss of a higher order transverse mode to that of the primary transverse mode, is calculated to obtain the optimal diaphragm diffraction loss sensitivity. The dependence of the lower limit of MSR (LLMSR) for a RLG on its gain level as well as its total mirror loss is investigated both numerically and experimentally, with the results showing that the higher the gain level, the higher the LLMSR, while the higher the total mirror loss, the lower the LLMSR. These results will be of great significance for the MSR optimizing control during the resonator alignment of RLG.