Abstract: The abrupt climate change of wetness in China from 2100 BC to 1800 BC is examined according to historical documentations, archaeological evidences and palaeo-climatic proxy data. The results show that there was a period with predominance of floods before the foundation of the Xia Dynasty (2070 BC). The folklore of "Regulation of floods by Great Yu" marked the ending of the period with floods. Climate turned to dry around the establishment of the Xia Dynasty. There are evidences to show that the annual precipitation reduced by 20% within a period less than 300 years. This change may be acknowledged as an event of abrupt climate change. The evidences show that change from wet to dry condition probably caused the collapse of archaeological cultures in China except in the central part of the main land area, where development of Chinese civilization leaded to the foundation of the Xia Dynasty.

Key words: Xia Dynasty, abrupt climate change, ancient Chinese civilization