Pipeline cable in southwest mountainous areas goes through many complex areas (mountains, rivers, tunnels, farmland, etc.). By geological deformation, man-made damage often leads to fiber core broken, and seriously affects the safety of pipeline production and transportation. Based on the Rayleigh scattering principle of light, the return time of scattered light can be detected, and the position of fault points can be judged. Finally, the vibration signal characteristics around the cable can be collected and analyzed. Due to the difference of surface structure and background noise in different areas, the collected signals are different. In this paper, after processing and analyzing the optical cable signals with different terrain, the external signal characteristics received by the optical cable in different regions are summarized, which helps to perceive the status of the pipeline optical cable line in a complex environment. The results in this paper can provide decision support for the safe operation of the pipeline, and achieve the purpose of early warning, which facilitates the construction of the pipeline safety early warning system in the future.