Abstract: Endowed with abundant hydropower resources,the upstream of Jinsha River is going to witness thirteen cascade hydropower stations in planning.The hydrological and sediment situation and its changes will have significant impact on the construction,dispatching and operation of the hydropower stations.In this paper,the variations of water and sediment in the upper Jinsha River in recent five decades are examined according to measured hydrological and sediment data of Gangtuo,Batang and Shigu hydrological stations.Results unveiled that the interannual runoff and sediment discharge in the upper Jinsha River presented increasing trend,and the increase of sediment discharge was obviously larger than that of runoff.In the meantime,the correlation between water and sediment and the double accumulation curve were both changing.The proportion of runoff in flood season was relatively stable during the year,and the concentration of sediment discharge in flood season was more obvious.Affected by the Baige large landslide in 2018,the proportion of sediment discharge in October and November,2011-2020,was higher than that in the past.The main factors leading to the changes of water and sediment in the upper Jinsha River include rainfall changes,large-scale landslide events and human activities.The Baige landslide and the following barrier lake led to a 91.7%-148% increase in sediment discharge in 2018 and 2020 compared with the average value in recent five decades.

Key words: upper Jinsha River, cascade reservoirs, runoff, sediment discharge, tendency