the unreasonable human activity is one of the key factors for soil erosion and sedimentyield. Irrational developing ofrare earth m ine ongdonggou watershed,Xinfeng County,induced to serious sediment silting in the river channel,and thetotal silting sediment was 30193 tiven the 7500m river channel estimated by measuring the siltiveng sectiveon. Based on the sediment delivery ratio,soil loss in thewhole tershed was 3500t/km²,and soilerosive radius was more than 1150 t/(km² Erosion degree in the watershed was of middle erosion density. Soilloss from the tailings ofrare earth mine was the most serious sources for sedimentiven river,and the loss was 99 730t/km² with annual erosion amount greater than 34000t/(km³a) as the severest loss type. Among all the soil and water loss controlling easurements,managementofrare earth mine development should be intensified and con-trolling abandoned mine tailings should be as a key aspect.