| The Last Glacial is an important period in the study of global change. In the recent years numerous scientists have found that there appeared many abrupt climatic changes during the Last Glacial by studying the high-resolution achieves of environmental change such as polar ice-core, deep ocean sediment and loess- palaeosol sequence et al. The discovery of abrupt climatic changes and the aim of predicting the environmental change in the coming future of the study of global change make studies on the high-resolution sequence of environmental change a frontier and hotpoint of the study of global change. Because of their prominent advantages compared with other achieves of environmental change, the study of high-resolution sequence of environmental change during the late Quaternary mainly depends on the polar ice-core and deep ocean sediment. The study on the loess- palaeosol sequence is characteristic and advantageous field of our country in the study of global change. In the recent years the study on the loess- palaeosol sequence has obtained many achievements that have attracted the attention of the world, but it mainly relies on the indirect physical and chemical proxies. The study depending on biological proxies of the loess- palaeosol sequence was dropped behind.The climate of our country, especially that of Qinghai-Tibetan Plateau during the middle stage of the Last Glacial, which is equal to Marine Isotope Stage (MIS) 3 showed different characteristics from the climate recorded in the deep ocean sediment and polar ice-core. The o18O curve of Guliya ice-core demonstrated that there appeared Episode of Strengthened Summer Monsoon, which is also called High Temperature and Large Precipitation Event. The climate of this period is almost as warm and wet as the stage 5e of the Last Interglacial. The mean temperature is 2-4 C higher and the precipitation is much larger than that of the today, the Holocene which we live in. While in the climatic records of deep ocean, Antarctic and Greenland ice-core, Marine Isotope Stage (MIS) 3 is a weakly warm period, though a little warmer than Marine Isotope Stage (MIS) 2 and Marine Isotope Stage (MIS) 4, evidently colder than the Last Interglacial and Holocene favorable period. Research on the high- resolution sequence of vegetation change during the middle stage of the Last Glacial in the Xishan Mountain can reveal the vegetation and climate of monsoon area of East China during this period and be of great significance to identify the area affected by Qinghai-Tibetan Plateau.We selected Dongzhaitang profile in the Zhaitang Basin of Xishan Mountain, Beijing area from which the Malan Loess got its name and study the sequence of vegetation change recorded in the Malan Loess of Xishan Mountain by means of spore-pollen analysis. Wesampled the palaeosol or buried soil of this section formed during the middle stage of Last Glacial at the interval of 10cm and totally we got 40 samples for spore-pollen analysis. We adopted the analytic procedure that is developed by Mingjian Wei (personal communication) to treat the spore-pollen samples. A known amount of lycopodium spores was added to each sample to calculate the concentration of pollen (grains/gram).Pollen was examined at magnifications of 100+ and 400+ and identified using modern pollen collections and published atlases. According to the derived spore-pollen percent diagram and spore-pollen concentration diagram, the sequence of vegetation change recorded in the Malan Loess of Xishan Mountain, Beijing area is as follows:Zone P1: In this zone the herbal pollens were overwhelming and the total pollen concentration was relatively high, so the vegetation during this period was arid grassland.Zone P2: There appeared two peaks of the concentration of arboreal and shrubby pollens and in arboreal and shrubby pollens the percent of pollens of deciduous broadleaf trees is comparatively high. It showed that the vegetation of this climatic stage was meadow or sparse forest steppe. This zone can be divided into two sub-zones: P...
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