First, writers proves the accuracy and stability of dry bulk density values measured by the oil-socked method based on comparative experiments; then the dry bulk density of loess-paleosol sequences about 70 m thick from L9 to S0 in Lingtai section, Gansu Province, is measured by the oil-socked method. The dry bulk density variations show that the dry bulk density of paleosol layers is higher than that of their overlying and underlying loess layers. The former values change from 2. 05 to 2. 18 g/cm3, the latter from 1. 85 to 1. 98 g/cm3. The average values of dry bulk density from L9 to SO change very little as the burying depth increases, which indicates that natural compaction contributes very little to the dry bulk density. Through a comparison between the magnetic susceptibility and dry bulk density variations, writers find that the dry bulk density variations, which are controlled by the aridity of the eolian source region, the strength of atmospheric circulation and the climatic conditions of the deposition area, not only record the alternation of East Asia winter and summer monsoons on the orbital time scale, but also reveal information of more frequent variations of the East Asia monsoons during the typical glacial periods.