Abstract: The Mu Us Desert，located in the northwestern fringe of the East Asian monsoon region，is sensitive to climate variations. The desert is characterized by mobile，semi­fixed and fixed sand dunes. At present，the Mu Us Desert is a mosaic of partially to fully active small transverse ridge dunes and large stable sand sheets，most of the dunes in the Mu Us Desert are transverse dunes aligned northeast­southwes，reflecting the regional pattern of sand­moving winds controlled by the cold and dry northwest winter monsoon. Due to its high deposition rates and high sensitivity to climate change，alternating units of dune sands and sandy paleosols in the Mu Us Desert recorded multiple episodes of dune construction and stabilization，in response to strengthening­weakening fluctuations of the East Asian monsoon. However，the aeolian sequences in the desert are often episodically interupted，seen as unconformities，non­aeolian deposition，and mixing of sediments，caused by strong wind erosions. Difficulties for compilation of a continueous sedimentary sequence can be overcome by dating sand dune activities at multiple sites，ultimately producing a high­resolution record of sand dune development and climatic change history. Chronological control is crucial in such reconstructions. Desert evolution and climatic change of high resolution in the Mu Us Desert are still poorly understood in part due to limited numerical dating results. In order to further examine the Late Pleistocene sand dune development and climatic changes in this region，five sand dune sections along a northwest­southeast transect in the Mu Us Desert were investigated and sampled. The chronological framework was constructed by dating 19 samples using quartz optically stimulated luminescence(OSL)and single aliquot regenerative­dose(SAR)protocol. A dose recovery test and a preheat plateau showed that the SAR protocol is appropriate for equivalent dose(De)determination for the samples under study. The concentrations of uranium，thorium and potassium were measured by neutron activation analysis. Magnetic susceptibility was measured on a mass of 10g of ground sediment with a Bartington MS2­B Magnetic Susceptibility Meter. The grain size was determined using a Mastersizer­S laser analyzer with(NaPO3)6 as dispersing agent after pretreatment with 10% HCl and 10% H2O2 to remove secondary carbonates and organic material respectively. Combined with lithologic stratigraphy，grain size，magnetic susceptibility and the luminescence chronology obtained，the sand dune development and climatic changes in the Mu Us Desert during the Late Pleistocene are discussed. Aeolian sand layers with wind­ripple lamination imply lower effective moisture，low vegetation cover and sand dune mobilization. The sandy paleosols represent higher effective moisture，higher vegetation cover and weak aeolian activity. Our results indicate that the Mu Us desert experienced multiple alternations of mobile and fixed episodes: the sand was mobilized approximately at 91.0ka,71.0ka,48.0ka,22.0ka,11.6ka,5.0ka,1.1ka,1.0ka,0.4ka，and was fixed approximately at 65ka and Holocene optimum period(8.5～5.0ka). The more and thicker sand layers and increasing coarsening of grain size suggests an increased aridity trend in the Late Pleistocene. More dating work is required in order to further reconstruct high­resolution records of aeolian development in the Mu Us Desert.