The Horqin dunefield, which is located in margin of the region dominated by East Asian monsoon circulation,is sensitive to climatic changes. However, paleoclimatic and the border changes of Horqin dunefield during Late Quaternary remain poorly understood, partly due to lacking high quality age controls. In this study, optical stimulated luminescence （OSL）technique and multi-proxy analysis of the sediment sequence from Horqin dunefield,including sedimentary facies, magnetic susceptibility and grain size distribution, was used to document the changes of paleoclimate and the borders of the dunefield since Last Glacial Maximum （LGM）. 20 typical dune sand sections were dated by OSL technique and 85 luminescence ages at the LGM have been obtained. It suggests that the dunes were mobilized with cold and dry climate during 26 ~ 12ka. Subsequently, the dunes changed from large-scale active to local stabilized with relatively warm and wet climate during 12.0 - 9.5ka. After that,the dunes were completely stabilized during 9.5 - 2.5ka with the climate was the warmest and most humid. After that, several mobilization/stabilization cycles of the dunes which were associated with dry-cold/ wet-warm variations occurred since 2.5ka, the dunes have been activated within the entire region after 1.5ka. On the basis of these dating results and the spatial- and temporal- distribution of the sand deposit, we conclude that the Horqin dunefield expanded at least 26km to south and 30km to north during the Last Glacial Maximum, at the same time,the eastern border was limited by the East Liao River as that of the present. The Horqin dunefield expanded around 2.05× 104km2 in the Last Glacial Maximum, 37.7% larger than that of the present area. During the Holocene climatic Optimum, the mobile dunes were fully stabilized in the Horqin dunefield. These climate and environment changes in Horqin dunefield can be regarded as a regional response to the global climate changes.
