The Yadong?Gulu Rift, the largest north?south?trending extensional system in southern Tibet, has complex tectonic?geomorphic features. This study investigates the major faults in the Kangmar area using 12.5 m ALOS?DEM data to evaluate fault segmentation and its surface expressions. Topographic metrics, including elevation, slope, local relief and swath profiles, were extracted from the DEM, and hypsometric integral (HI) values were calculated for 312 drainage basins, with all results integrated with field geological observations. The southern segment of the Chumba Yumco Fault records greater cumulative uplift than the northern segment, yet exhibits lower HI values due to intense karstification and fluvial downcutting—suggesting a quasi?steady?state balance between rock uplift and erosion. The Nierudui Fault shows marked along?strike segmentation, with stronger activity at both ends and weaker activity in the middle. Multi?parameter comparisons further indicate that the Nierudui Fault produces stronger geomorphic responses than the Chumba Yumco Fault, pointing to fault geometry as a primary control on landscape evolution. Tectonic activity largely determines the regional topographic framework, whereas lithology and precipitation play secondary, modulating roles. Drainage basins around Suolari Peak yield HI values > 0.51, reflecting a youthful erosional landscape probably driven by rapid differential uplift. This area, located at the junction between the rift and the South Tibetan Detachment System, warrants focused attention in future studies of active tectonics in southern Tibet.