Abstract: The fiber-Bragg-grating (FBG) self-sensing anchor cable was used to carry out an experimental monitoring application in the foundation pit support engineering of a stadium with a "double-row pile + anchor cable" in a muddy geological environment. The monitoring results show that as the FBG self-sensing anchor cable can efficiently monitor the cable force at each moment, it accurately obtains the cable force change during the construction process of prestressed tensioning. In addition, the monitoring range of the self-sensing anchor cable is its full length. Given the cable-force growth curve of each measuring point, the anchoring effect of the corresponding part of the anchor cable and the rock and soil mass can be inferred. The long-term monitoring results indicate that the self-sensing anchor cable synchronously responds to changes in the displacement and deformation of the supporting structure accurately. Therefore, it provides reliable data support for the quality and safety of anchor cable engineering.