Abstract: The southern mountainous area in Anhui province has complicated landform and geological structure, which is the most hazardous geological disaster-prone area in Anhui province. The distributed fiber optic sensing (DFOS) technology was used in the southern mountainous area in order to overcome the defects of conventional sensors, and was combined with the characteristics of the engineering environment of its landslide deformation. DFOS technology included deep in-situ monitoring, soil pressure and groundwater monitoring, and the landslide stability was also analyzed. The results show that the landslide is in initial deformation stage or uniform deformation stage during the monitoring period, and the maximum thickness of the landslide body does not exceed 12.5 m. The cumulative displacement and displacement rate of the landslide decrease with increasing depth, and the variation becomes minimal at a depth of approximately 12 meters. Additionally, the soil pressure fluctuations at different depths are generally small, and the rate of groundwater level fluetuations is in a mutually offsetting state. The landslide as a whole is in a relatively stable state. The research results could provide scientific basis for revealing the internal evolution laws of landslide in the southern mountainous area, implementing effective early warning and prediction, and promoting the popularization of optical fiber monitoring technology.