Abstract:The essay researches the drill core samples from the center of Dalangtang salt lake in the western of Qaidam basin. By the study of U series chronology, we get the sediment sequence of lake strata since 140ka BP in this area. The sedimentary characters indicate that this area suffered 8 times salifying periods and 6 times freshening periods. The main minerals include the halite, gypsum, mirabilite and bloedite during the salitying periods, and the main minerals include the clay minerals(the illite mainly, the chlorite and kaolinite secondly ), carbonate(the calcite and dolomite mainly), quartz and feldspar during the freshening periods. Correspondingly, the carbon and oxygen isotope analysis in this period indicate that the changes from 140 to 113 ka BP(92~ 84m) of drilling core was corresponding well with the evolution stages (5e)during the last interglacial. From 113 to 93 ka BP(84~78m)(5d), the component of oxygen isotope indicate the it existed several climate fluctuations during this time. The mediumcoarse grain mirabilite as the index minerals of low temperature gets 2 meters thick from 78~80m of drill core, reflecting the temperature of water changes frequently. Besides, the three periods including 93~87 kaBP(78~74.6m), 87~79.5 ka BP(74.6~67.5m), 79.5~76 ka BP(67.5~63.5)are corresponding with the periods stages of 5c, 5b, 5a after the last interglacial period respectively. From 76 to 72ka BP(60~64m),the oxygen isotope becomes heavy quickly (-4‰~-8‰(PDB)), indicating the temperate goes down and the water becomes salty obviously; from 72 to 30 ka BP(60 ~16 m), the components of carbon isotope and oxygen isotope become heavy, reflecting the character of dry and cool climate, and the two salty periods appearing in this period, representing the stage of cool and dry climate; from 30 to 14 ka BP (16~0 m), the component of oxygen isotope become heavy obviously, representing the coming of the last glacial and the end of lake water sediment.