Abstract: In order to reconstruct the paleoclimate and explore its evolution model and response to the global paleoclimate during the Mid−Late Pleistocene in the Bayinhua Basin, West Ujimqin Banner, Inner Mongolia, the sporopollen of ZK03 and ZK04 in the basin were systematically identified. Combining Coniss analyze with Co−existence Approach, we quantitatively reconstruct the palaeoclimate parameters in research area. 68 genera are identified and divided into 3 assemblages as: (Ⅰ) Pinus−Betula−Typha assemblage; (Ⅱ) Quercus−Ephedra−Artemisia assemblage;(Ⅲ) Cyperaceae−Typha−Polypodiaceae assemblage. The age of assemblage Ⅰ and assemblage Ⅱ was Middle Pleistocene, while the age of assemblage Ⅲ was Late Pleistocene. The vegetation types experienced the transformation as broadleaved − steppe type with a small amount of coniferous forest vegetation→broadleaved − steppe type vegetation→savanna− steppe vegetation. Palaeoclimate experienced three periods of transition from relatively warm and humid climate to relatively warm and cool semi−arid climate and then to relatively warm and humid climate. The annual average temperature and annual rainfall corresponding to each period also showed a numerical process of change from high to low and then to high. The trend from cool to warm at the turn of the Middle Pleistocene/Late Pleistocene can be well coupled with the trend of global mean temperature that indicated by the oxygen isotopes of Greenland ice core.