Abstract: The paleoenvironment is established by analysis of grain size,magnetic susceptibility,organic matter and carbonate content of the sediments at Lujiagou section, Dingxi in Gansu Province and ¹⁴C dating.The results from climatic indexes from the section show that climatic changes in the past 14 900 cal.aBP were instable in this area and can be divided into four periods:the last late-glacial(14 900~11 200 cal.aBP) during which the climate was still cold and dry; the early Holocene(11 200~7 560 cal.aBP)with summer monsoon strengthening and the climate becoming warmer and wetter; warm and wet climate dominated the middle Holocene (7 560~3 600 cal.aBP);the late Holocene(3 600~1 200 cal.aBP)when the climate became drier and cooler and the dust-fall was strengthening. Four paleosoils were formed, whose dating was 10 100~8 000,4 350~4 100,3 900~3 700, and 2 800~2 560 cal.aBP respectively.