Based on systematic experiment analysis of trace elements including Mn,Ni,Cu,Ba,La,Rb and Sr for Longquancun profile covered by the front edge of the second terrace in the Danjiang River Valley,these characteristics reveal the weathering intensity of Loess - paleosol sequence and its palaeoclimatic significance since late Pleistocene. At the same time,the typical loess on the loess plateau is compared. Results are shown as follows: the fluctuation characteristics of 7 trace elements in the profile are direct reflection of climate change. Mn, Ni,Cu,Ba and Rb have high values in paleosol layer (S_1,S_0 ),low values in the loess layer (Lt,L_2,L_1 ); However,La and Sr are high in loess layer (Lt,L_2,L_1 ),low in paleosol (S_1,S_0 ). The environment changes since late Pleistocene have been clearly recorded by the changes in the trace elements in this area. That is,the climate was warm and the pedogenesis was stronger in the period of the palaeosol formation. In the stage of the loess accumulation,the climate was cold and arid,so the weathering pedogenesis was very weak. Among them, during the period of the formation of Malan loess,the climate experienced a short period of warm. The trace elements in the Danjiang region are similar to those in the Loess Plateau,which indicates that the two regions are basically the same under the influence of the late sedimentary environment. The chemical weathering of LQC profile was stronger than that of the loess and paleosol in Luochuan.