Giant　landslides　have　frequently　occurred　in　deeply-incised　valleys　during　the　topographic　development　of　the　Tibetan　Plateau,　and　these　landslides　commonly　blocked　rivers　and　in　turn　affected　fluvial　processes.　The　giant　Qianjincun　landslide,　with　a　volume　of　-110　x　10(6)　m(3),　created　the　highest　natural　dam　among　all　the　completely　river-blocking　landslides　identified　along　the　trunk　of　the　Nu　River　in　the　southeastern　Tibetan　Plateau.　This　giant　landslide,　which　developed　on　a　granite　hillslope　and　dammed　the　river　with　a　height　of-175　m,　was　dominated　by　long-term　fluvial　incision　responding　to　uplift　in　one　of　the　deepest　valleys　in　the　world.　The　dammed　lake　was　breached　around　the　end　of　the　Dali　glaciation　(-10　ka),　and　the　deposits　remaining　in　the　valley　indicated　an　earlier　landslide　from　the　opposite　failure　source　beside　the　Qianjincun　landslide.　The　Geduicun　landslide　on　the　right　bank　evolved　from　gravitational　deformation　of　toppling　controlled　by　schist　foliations,　while　the　Qianjincun　failure　on　the　left　hillslope　was　governed　by　the　seismically　-triggered　detachment　of　granite　cut　by　rock　joints.　The　kinematic　process　of　the　Qianjincun　landslide　was　numerically　investigated　under　seismic　loading,　indicating　high-velocity　sliding　from　a　thousand-meter-high　source.　In　comparison　to　the　soft　rock　failure　preceded　by　the　long-term　gravitational　effect,　the　mass　move-ment　on　the　granite　slope　was　catastrophically　induced　by　dynamics　with　high　initial　kinetic　energy,　and　the　subsequent　overwhelming　river　blockage　transiently　caused　stronger　landscape　evolution　than　any　other　land-slides　in　the　catchment.　The　inventory　of　river-damming　landslides　compiled　along　the　trunk　of　the　Nu　River　suggested　a　prominent　tendency　that　all　the　dammings　occurred　in　the　region　where　the　relief　is　greater　than　2000　m.　The　analysis　provided　the　power-law　correlations　of　the　geomorphic　parameters　of　dams　that　can　help　predict　the　disastrous　effects　of　future　river　blockages.　The　insight　into　landscape　feedbacks　between　giant　landslides　and　fluvial　processes　could　contribute　to　effective　risk　assessments　of　disaster　chains　in　high-relief　reaches.