Fluctuations of closed lake level results from the relative changes of lake water and volume of lake basin. For the closed-lake was constructed by drainage input lake and evaporation of lakesurface at the thousand years scale. So it was very sensitive that the fluctuations of closed-lake level respond to the changes of climate.It has provided trustworthy and easy comparison evidence to analyse the geomorphology of lake basins, lacustrine deposits, geochemical information and orgnisms ecological character reserved in the lacustrine deposits. Since 17000 a.B.P. the closed-lake level was shrinking, but appeared three stages of high lake level in the Middle kunlun Mountains. Recently, the closed-lake lever is shrinking. In future, the closed-lake level will shrink continually.