Abstract:Double mass curve(DMC)method and rating curve method were applied to explore the loop characteristics of the suspended sediment concentration based on measured daily discharge and suspended sediment runoff from 1960 to 2015 of Huangfuchuan Basin in the midstream of the Yellow River. The results show that the average annual runoff and the mean sediment runoff was 111 million m3 and 31 million tons respectively. Significant reduction tendency was revealed with a reduction rate of 0. 0331 billion m3/a and 0. 0101 billion t/a, respectively. 1979 and 2003 were two turning years, exhibiting distinct phase characteristics. In addition, the rating curve can be fitted with a power exponent function and the relation between discharge and sediment does not show significant deviation. Vegetation recovery together with soil and water conservation projects play an important role in sediment reduction. Finally, there are 5 patterns of Concentration-Discharge(C-Q)relation loops for typical hydrological events, including clockwise, counterclockwise, figure-eight, reverse figure-eight and linear loops, which describe different sediment transport features during a flood.