Under the current background of global warming, the frequency of extreme weather events,represented by floods and droughts, are increasing continuously, and the impacts of which on human society are also growing. So it is very important to explore regularity of related natural disasters occurring in the future. The Medieval Warm Period (MWP) is the last warm period from nowadays, studying occurrence regularity of natural disasters during this period could provide certain theoretical basis for disasters prevention in the future. Taking the north Henan area as a case, through the statistics and analysis of historical documents during the MWP (i. e.901 - 1 300 AD), the flood feature in the area during MWP such as occurring intensity and occurring time were studied. The results indicate that there are 97 times of floods during the MWP, approximately once every 4.12 years on average. Flood dis-asters are mainly first grade ones, which account for 84.54% of the total, followed by second grade ones with percent of 15.46%, and there is no third grade floods during the MWP. In respect of time, floods are more in the early period and less in the later period. The floods have obvious seasonal difference and the floods occurring in summer and autumn are the most, accounting for 59.6% and 32.6%, respectively; then followed by spring and winter, only with percent of 4.5% and 3.4% respectively.