The Qaidam Basin has undergone drought for a quite long time,and the deep lacustrine facies in the western Qaidam Basin records the process of environmental evolution. Based on the analysis of sporo-pollen in the sediments from Drilling core ZK06 in Dalangtan and total concentration change of pollen deposition as well as migration,mutual growth and decline change of regional representative coniferous tree plants and herbaceous plants and peak features of fern spore, in combination with the U-series dating data, vegetation succession and environmental evolution since the last interglacial period in study area were discussed and the climate and environment in various stages of MIS5-MIS2 in the western Qaidam Basin were compared. It is concluded that along with the phased uplift of the Tibetan Plateau and under the influence of global climate change,although the overall regional vegetation alteration is not obvious,yet the pollen concentration was very low in the salinization period of lake water, reflecting that the vegetation was sparse under dry salinization environment. The total pollen concentration was higher in clastic sedimentary period of lake water desalination,indicating that the climate turned humid,the area of montane forest around the basin increased and basin grassland expanded. Since MIS5 stage,the overall trend was that the thickness of salt gradually increased,the thickness of mud debris layer gradually decreased,the total pollen concentration gradually decreased,herb pollen percentage gradually decreased and tree pollen percentage gradually increased. Because the changes of river flows induced by the glacial meltwater in the study area greatly affected water supply to the lake,the factors affecting sanilization and desanilization of lake water and the change of lake water level were more complex. In the MIS1 stage Dalangtan Saline Lake in western basin completely dried up,in the Holocene megathermal period the rise of lake water and desinilazation did not appear, perhaps resulting from the control by the regional tectonic movement effect.