Based on records of the Guliya Ice Core (35.6°N,80.5°E) pollen and high lake levels in the Tibetan Plateau and its adjacent area, there appeared a particular warm and wet stage with the mean temperature 2-4℃ higher and large precipitation much more than that of the present.The reconstructed precipitations with Kutzbach's water and energy balance model of closed lake basin are estimated up to 640mm,560mm and 260mm in the Qinghai Lake,Chabyer Caka/Laguo Co, and Akesaiyi/Tianshuihai Lake which are 1.7,3,5 times of thatin the present respectively.The large precipitation extended to the north slope of Qilian Mountains at the north and to Yunnan Province at the south-east of Qinghai-Xizang plateau had played an important role in the geomorphological evolution of some liveis originated from the Tibetan Plateau.The upstream river pattern of the Yellow River same as present, had come into being for the Zoige Palaeolake overflowing to meet the headward erosion of the Yellow River in the borderland of Gansu and Sichuan Provinces.The formation of the deep channels with their bottom lower than present sealevel in the Three Gorge area in the middle reach of the Yangtze River might be related to high speed flood resulted from the upstream large precipitation in the Tibetan Plateau.While flood currents were narrowish and hindered in the gorge channel the high energy turbulent flow carried large quantitative gravels to cut the river bottom and formed the deep channels (formed before 40kaBP).Some ¹⁴C dates of the buried woods between 40-30kaBP, in the gravel deposits at the channel bottom indicated the upper mechanism process.Some separated closed lake catchments in the Tibetan Plateau, such as,Serling Co,Nam Co and Pangkog Co were merged into a great closed catchment by water overflow.This high lake leveleventis mainly caused by the particularly strong Indian monsoon for enhanced cross equator aircurrent from south hemiphere over Indian Ocean activated by high solar radiation of precession cycle in low latitude.On the other hand we infer in the period between the event H4 (35.5kaBP) and H3 (28-27kaBP) the southward-shifted westerlies,from the warm North Atlantic Ocean for northern Eurasia ice sheet gave passive impact on high lake levels for arousing much precipitation.