基于光纤瑞利散射的相位敏感光时域反射仪（Φ-OTDR），具有对环境变化敏感、响应速度快等特点，是分布式光纤传感领域最重要的分支之一。然而，Φ-OTDR使用的高相干探测光波在散射过程中会不可避免地出现干涉衰落效应，相应位置会成为传感的盲区。此现象是多年来本领域的关注重点之一。本文首先简述了干涉衰落的产生机理和数学特征；然后，系统地介绍了Φ-OTDR的典型传感机制，以及干涉衰落对传感信号解调造成的影响；随后，全面地回顾了Φ-OTDR抗干涉衰落技术的研究历程；最后，对Φ-OTDR的未来发展进行了探讨。

The phase-sensitive optical time domain reflectometry (Φ-OTDR) utilizes distributed Rayleigh scattering sensing to achieve sensing, and it has the advantages of high sensitivity and fast response speed to environmental disturbances. It has become one of the most important branches in the field of distributed optical fiber sensing. However, the high-coherence lightwave of Φ-OTDR will inevitably induce interference fading during the scattering process, and the corresponding positions will become blind zones for the sensing system. Fading phenomenon has been a research focus in this field for many years. In this paper, we first briefly describe the generation mechanism and mathematical characteristics of interference fading. Then, typical sensing mechanisms of Φ-OTDR are systematically introduced, as well as the influence of interference fading on the sensing signal demodulation. In addition, the research progress of anti-interference fading technologies is comprehensively reviewed. Finally, the future developments of Φ-OTDR are discussed.