Abstract: Bureau of Hydrology and Water Resource of Sanmenxia reservoir area is located in the middle and lower reaches of Yellow River.The hydrologic stations of this area are distributed in Shanxi,Shaanxi,Gansu,Henan provinces.This area has much and coarse sand and is the key district to be treated.In many years,each hydrological station used the empirical value 2.70 g／cm3 as the sediment density and adopted the substitution method to get the sample water sand weight.In order to verify the value veracity,based on the tests from 1990 to 1995,it did several hundred density tests of sample sediment in reservoir and 12 hydrological stations of Yellow River main stream and important tributary in 2007 and 2013.According to the statistics analysis,it gets the sediment density value 2.71g／cm3 of Yellow River main streams and the sediment density value 2.73g／cm3 of Yellow River tributaries.