The phase-locking behavior of El Nio-Southern Oscillation (ENSO) in models from Coupled Model Intercomparison Project (CMIP) phase 5 to phase 6 is assessed in terms of the locking-month of ENSO peak and the sharpness of locking tendency. Overall, a robust improvement exists in CMIP6. Compared to CMIP5, more CMIP6 models truly reproduce the locking-month in November-January. Meanwhile, the sharpness of phase-locking in CMIP6 models also improves, though most of them are still far from the observations. The locking-month is verified to be highly corresponding to the phase of seasonal modulation of ENSO’s instabilities. The sharpness is mainly controlled by the intensity of this modulation and noise. Compared to CMIP5, CMIP6 models generally simulate these affecting factors better. Besides, models displaying an exaggerated semi-annual variation of ENSO’s instabilities simulate the ENSO phase-locking relative-poorly, and these models show no reduction from CMIP5 to CMIP6.

耦合模型比对项目（CMIP）第 5 至第 6 阶段模型中厄尔尼奥-南方涛动（ENSO）的锁相行为通过 ENSO 峰值锁定月和锁定趋势的锐度进行评估。总体而言，CMIP6 存在强大的改进。相比CMIP5，更多CMIP6机型真实再现了11-1月的锁定月份。同时，CMIP6 模型中锁相的锐度也有所提高，尽管其中大部分仍与观察结果相距甚远。锁定月被证实与 ENSO 不稳定性的季节性调制阶段高度对应。清晰度主要由这种调制和噪声的强度控制。与CMIP5相比，CMIP6模型一般能更好地模拟这些影响因素。除了，