This study presents a multi-point sensing system for cable fault detection based on fiber Bragg grating (FBG). The system detects vibration signals caused by cable faults through changes in the reflected power of the FBGs. By integrating time division multiplexing (TDM) technology, the system achieves multi-point fault detection and distinguishes vibration signals from faults at different cable locations. To verify the system’s feasibility, different fault scenarios were simulated. The results show that the system can detect the vibration signals caused by cable joint faults, successfully demodulate the corresponding frequency components, and reconstruct the strain applied to the FBGs. Additionally, to address the impact of front-end FBG on back-end FBG, a power compensation method was developed to improve detection accuracy. The proposed cable fault detection system facilitates online detection of cable joint faults but also reduces system equipment costs, offering a novel approach to cable fault detection.