Abstract: Liandeng Gully has historically experienced frequent debris flow disasters that often causes casualties, traffic disruptions, and river blockages. Based on field investigations and remote sensing interpretation, this study investigates the morphological changes in the gully, the characteristics of sediment sources, and the evolution patterns of debris flow. Using numerical simulation, the dynamic behavior of debris flow under various rainfall return periods was analyzed. The results indicate that debris flow initiation zones are concentrated at tributaries No. 2, 4, and 5 on the left side of the main gully, where channels have widened over time and material sources continue to accumulate. Under the rainfall frequencies of once every 10, 20, 50, and 100 years, debris flow disasters exhibit similar progression, with peak flow velocities at the gully outlet reaching 1.57 m/s, 2.01 m/s, 2.48 m/s, and 2.98 m/s, and debris volumes of 26,400 m³, 51,700 m³, 115,600 m³, and 187,600 m³, respectively. Under the 10-year return period rainfall scenario, debris flows can bury roads and block rivers, forming dammed lakes. In view of the characteristics of debris flow in Liandeng Gully, comprehensive mitigation and control measures are recommended, including source stabilization, channel bed reinforcement, barriers, and diversion works. The findings provide scitific supoprt for the study of high-frequency debris flow development and evolution, and serves as a reference for local disaster prevention and mitigation projects.