提出工作于谐振腔适度失谐时的克尔介质自锁模激光器易于开启和维持自锁模的理论。根据克尔镜锁模原理和动态可饱和高斯增益特性，利用激光传输矩阵理论，对系统进行了数值模拟计算，确证了最佳腔镜失谐角的存在．结论与已有的实验结果相符，并对它们赋予了新的合理解释。 The theory that Kerr medium self-mode-locked laser can work easily and maintain self-mode-locked mode is proposed. According to Kerr-mirror mode-locking principle and dynamic saturable Gaussian gain characteristics, the system was simulated by using laser transmission matrix theory, and the existence of the best detuning angle was confirmed. The conclusions are consistent with the existing experimental results and give them new and reasonable explanations.