The oft-com:office:smarttags" />Tianyuan Cave site is an important paleoanthropological site of late Pleistocene in China. The site was investigated and excavated in 2003 and 2004 by a team from the Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences. A large number of human fossils were unearthed. The skeleton is dated to be 42 000~38 500 calendrical years by using direct accelerator mass spectrometry radiocarbon, which falls into the MIS 3(Marine Isotope Stage 3). In order to interpret the possible environmental changes, especially the impact on human activities at Tianyuan cave, even in Beijing, the systematic analysis of the mammalian fauna, magnetic susceptibility, clay minerals as well as oxides from sediments was carried out by the authors in the paper. oft-com:office:office" />