Objectives: Numerous researches in lakes and ice cores of the Qinghai—Tibet Plateau, Chinese loess and cave records show that the Asian monsoon variety since MIS5 recorded the strong orbitaldriven evidence, and that MIS1~5 and even MIS5a—e are the most basic characteristic periods during the D/O cycle processes. The vast redearth of southern China is an important area influenced by the Asian monsoon, especially the East Asian monsoon. However, there has been little research, so far, on how it responded to the characteristic periods since MIS5. We study the "Xiqiao section" and the stratigraphic investigation in the vicinity of the Xiqiaoshan area in South China to reconstruct the climate and environmental changes in southern China during MIS5. Methods: We analysed the contents of the main chemical oxides SiO 2 , Al 2 O 3 and TOFE (Fe 2 O 3 + FeO) in sections, and discussed the distribution of main elementsSiO 2 , Al 2 O 3 , TOFE (Fe 2 O 3 +FeO). Also, we calculated the n (SiO2) / n (Al2O3) ratio (mole ratio) and alteration index CIA . Results: The results show that the contents of SiO 2 , Al 2 O 3 , TOFE, ratios of n (SiO2) / n (Al2O3) , and alteration index ( CIA ) values in the red clay of MIS5a in both sections are significantly different from those of the midsubtropical and southern subtropical regions of China, but quite similar with those of the tropics areas of Hainan Island and Leizhou Peninsula, especially, much close to those in Leizhou Peninsula. Moreover, tropics animals of Giant panda—saber—toothed elephant fauna of MIS5a, Hylobates sp. Rhinoceros sinensis , Megatapirus cf. angustus and Elephas ap. were discovered in Bishou Cave in the study area, to the west of the study area nearly 150 km from Xiqiao Mountain, tropics memebers of Giant panda—saber—toothed elephant fauna of MIS5a, Megatapirus cf. angustus, Rhinoceros sp. and Rhinoceros sinensis were also found in Luoshayan Cave. Therefore, it is suggested that the red clay of MIS5a in Xiqiao Mountain and nearby areas indicates the tropical climate in MIS5a andthe bioclimatic zone during MIS5a in Guangdong south to Nanling Mountain probably belongs to the edge of tropical climate. Conclusions: The result of this study has proved regional response to the global climate change at low latitudes in China during that period, and provided particular evidence to support the orbital driving force theory of climate evolution in geochemistry and paleontology.