Abstract: Lake sedimentary rhythm provides important information on the reconstruction of the palaeoenvironment and palaeoclimate. This paper presents a rare kind of saline sedimentary rhythm composed of mirabilite，borax and clay．To identify the origin and the climatic significance of the rhythm，we used 14C and U series isotopes to get chronological data，analysed pollen compositions, studied chemistry of different water′s and measured thicknesses of individual layers．Our study indicates that the sedimentary rhythm can be formed under the condition of enough source materials，closed morphological environment and climatic changes. During 20.6-20.5 ka BP. there was abundant vegetation and no mirabilite. The climate was warm and wet. Thick mirabilite layers and desert steppe suggest that from 20.5 to 11.4 ka BP the climate was drycold, and there were three warm pulses in 17.5-17.1 ka BP，15.9-15.2 ka BP and 14.1-13.4 ka BP．It became distinct warm during 11.4-10.1 ka BP when thin mirabilite layers and abundant vegetation were developed．From 10.1 to 7.5 ka BP，the cold climate was supported by thick mirabilite layers，decreased arboreal pollen and disappeared Pediastrum．During 7.5-4.97 ka BP, the typical plain composed of Artemisia and the thin thickness of mirabilite layer suggest relatively wetwarm climate，and the variable thicknesses of mirabilite indicate an alternative climate from cold to warm. There was a wetcold pulse during 7.0-6.2 ka BP for decreased Artemisia and increased hydrophyte．The absence of gramineous pollen and the increase in drysalt vegetation proposes a colddry climate and the increased salinity of lake water from 6.2 to 5.2 ka BP．