Prestressed concrete cylinder pipes (PCCPs), which are composite pipes, are widely used in cross-basin water transfer projects and urban underground pipe network construction owing to their low cost, long life, high pressure-bearing capacity, and ease of construction and installation. However, in the course of long-term service, PCCPs may undergo damage and fail to different degrees due to the combined effect of external loads, ion erosion in the soil, and uneven settlement of the foundation. Hence, long-term monitoring is essential for the safety evaluation and risk assessment of pipelines. In this study, a prototype centralized filament-breaking damage test was performed on a large-diameter embedded PCCP with an inner diameter of 3.4 m and a length of 5 m, revealing a correlation between the number (proportion) of broken filaments and the extent of PCCP damage. The results showed that the maximum wire breakage ratio of the PCCP specimen was approximately 20% under the design internal pressure. Meanwhile, a safety monitoring method for PCCPs was established based on distributed acoustic sensing, which helps monitor destructive events, such as wire breakage and retraction, and cracking of the mortar protective coating and core concrete during PCCP operation. Moreover, the vibration signal pattern was analyzed, and its characteristics were deciphered, providing a new means of monitoring the long-term operational safety of PCCPs and providing early warning.