A detailed magnetostratigraphic investigation has been carried out on a 1000 m thick sequence of Liang ZK02 Borehole in Dalangtan, northwest of the Qaidam Basin. Magnetostratigraphic results show that the B—M boundary of borehole is located in 315m, Jaramillo subchron and Olduvai subchron are located in 405~430m and 772~816m, respectively. Three large environmental changes in Quaternary, occurred around 25~22Ma, 12~07Ma and 04Ma, are identified based on integrated analysis of evaporites, clastic rock and sporo pollen record. The uplift of Xizang(Tibetan) Plateau was probably the main reason for these environmental changes, paleoclimate of Qaidam Basin transferred from cool, wet climate to cold, dry climate in the end of Early Pleistocene to early Middle Pleistocene because of the uplift of the Xizang(Tibetan) Plateau. The trend of aridification caused by uplift is not intensified gradually, the climate became wetter in humid period since the end of Early Pleistocene, which might result from intensified strength of summer monsoon caused through uplift of Xizang(Tibetan) Plateau, where the glacier and snow covered areas increased.