?137)Cs──an artificial radioactive isotope which is resulted from weapons testing mainly in1950s and 1960s was used as a
tracer in
soil erosion and
sediment transportation. The soil erosionand sediment transportation of the loess hill(round loess mound)and slope land are discussed,aswell as ￣(137)Cs distribution characteristic on the loess hill and slope land is analysed. Moreover soilerosion modulus of the loess hill and slope land is calculated, simultaneously sediment transporta-tion characteristic and ratios of the loess hill and slope land are analysed. The main results are asfollows:1.The regional background value of ￣(137)Cs is 2270Bq/m￣2 from content and depth distribu-tion of ￣(137)Cs of background profile.2.￣(137)Cs content is low on the middle upper sectors of the slope land,and high on the bottomof the slope land,it indicated that intense soil erosion takes place in the middle upper sectors ofthe slope land and a part of soil deposited on the bottom of the slope land.3.The soil erosion medulus of loess hill and slope land are 1510 11560t/<(km)￣2·a>,the average soil erosion modulus of profile line 1 and profile line 2 are respectively 8890 and6380(t/<(km)￣2·a>), the value is a half of the reported soil erosion medulus that ranged 14500 17 500t/<(km )￣2·a>. The soil depositional rates of profile 6 and profile 14 arerespectively 280 and 4 230(t/<(km)￣2·a>)on the bottom of slope land. 4.The sediment transportation ratio of the slope land is 0.96.