Abstract: 【Objective】Landslides exhibit significant potential for transformation into debris flows under certain conditions, resulting in a significant expansion of hazard zones, disaster magnitude, and destructive intensity. Historical debris flow events in Zhangping Gully, Lanping County, Yunnan Province, indicate that intense rainfall is the primary triggering factor. The prevailing formation process involves rainfall-induced landslides sliding into the gully channel and subsequently transforming into debris flows. A high-risk landslide has recently developed at the headwaters of the northern branch of Zhangping Gully, exhibiting clear deformation signs and posing considerable risk. 【Methods】This study employs data collection, InSAR deformation interpretation, multi-temporal remote sensing interpretation, drone-based photogrammetry, detailed field investigation, and integrated analysis. 【Results】This study characterizes the developmental features of high-risk landslide sources, elucidates the landslide-debris-flow transformation mechanisms, and proposes targeted mitigation strategies considering existing engineering controls. 【Conclusions】 (1) The DisiAri landslide has a volume of approximately 350,000 m³ and is a soil landslide developed in loose accumulation layer. The deformation of the landslide has intensified since 2020, and it is currently in an accelerated deformation stage. It has the proper topographic, material, and hydrological conditions to transform into a debris flow. (2) Based on different initiation processes, three distinct transformation modes are identified: the frontal erosion-induced activation, holistic mass conversion and river damming-breaching dynamics. The latter two generally produce larger-scale debris flows with stronger destructive potential. (3) For the DisiAri landslide, enhanced monitoring and early-warning efforts are recommended, along with investigation and evaluation of its potential to transform into a large-scale debris flow. Considering this possibility, dredging and capacity-restoration of existing debris-flow control structures in Zhangping Gully are advised, together with a re-evaluation of their load-bearing capacity.