利用Ｎｙｑｕｉｓｔ稳定判据证明了控制通道具有纯滞后的一阶控制系统能稳性的充分必要条件。在满足能稳性的条件下，得到了保证一阶闭环系统滞后相关稳定性控制律应满足的充分必要条件。给出的条件简捷，为判断时滞系统的稳定性和设计时滞控制系统镇定控制律提供了理论依据 The Nyquist stability criterion is used to prove the necessary and sufficient conditions for the stability of first-order control systems with purely delayed control channels. The sufficient and necessary conditions for the control law of lag-related stability of first-order closed-loop system to be satisfied are obtained under the condition of stability. The presented conditions are concise and provide a theoretical basis for judging the stability of the time-delay system and the stabilization control law of the design-time delay control system