Abstract:[Objective] A comprehensive evaluation of the causative factors and mechanisms of debris flows in Baise City, Guangxi, China was conducted , in order to provide scientific basis for the prevention and risk prediction of railway debris flow disasters in mountainous areas. [Methods] Based on a field investigation, historical remote sensing image analysis, among other methods, the characteristics and disaster-causing factors of railway debris flow in mountainous areas were analyzed. The debris flow occured on April 19th, 2024 (“4·19”)was theoretically calculated to obtain the dynamic parameters such as rainstorm peak discharge, debris flow peak discharge, and the quality of run-out solid materials under different working conditions. [Results] ① The railway debris in Baise City, Guangxi has a typical valley type flow, with a catchment area of 0.48 km2, a main gully length of 1.03 km, an average longitudinal slope of 319.42‰, a relative height difference of 329 m, and well-developed material sources in the gully, including channel, slope, and landslide material sources. ② The peak discharge of the rainstorm caused by the “4·19” rainfall was 6.23 m3/s. After the superposition of various environmental degradation factors, the peak discharge of the debris flow reached 23.16 m3/s, which was 3.72 times greater than the peak discharge of the rainstorm, and 1.934×104 m3 of solid materials move with this discharge at one time, which exceeds the interception and discharge capacity of existing measures. ③ In recent years, deforestation, excavation of access roads, forest fires, and arid climate have led to environmental degradation in the watershed, which are the main reasons for the occurrence of debris flow. [Conclusion] The environmental degradation is the core reason for the formation of debris flow in study area. The dynamic parameters such as the discharge of debris flow under different working conditions are consistent with the actual situation, which can provide a theoretical basis for the design of the prevention and control project.