A long-distance optical cable physical safety monitoring system, including a light source module, a light interference module, a sensing module, a reflection module, a photovoltaic conversion module, and a data processing module. The light interference module is use for dividing a light beam into multiple light beams; the sensing module is use for transmitting the multiple light beams; the reflection module is used for reflecting the multiple light beams to make the light interference module to output an interference signal; the photovoltaic conversion module is used for converting the interference signal to obtain a data signal; the data processing module is used for processing the data signal. The long-distance optical cable physical safety monitoring system is passive, low in energy consumption, anti-jamming, low in false positive rate, simple in construction, and convenient in maintenance.