Based on long series of precipitation data, this study analyzed the inter-decadal variations of annual precipitation, flood seasonal precipitation in the extensive 8 river basins (the Yangtze River, the Yellow River, the Huai River, the Songhuajiang River, the Liao River, the Pearl River, the Haihe River, the Tai Lake) in Chinas Eastern Monsoon Region.The study collected and processed the extreme series data of maximum daily rainfall of 1,741 gauging stations in recent 50-60 years, and analyzed the variation characters of extreme rainstorm events against the climate change background.Extreme hydrological events of flooding were defined as those medium and above floods that happen once every 10 years, 20 years, 50 years and 100 years.Based on long series of annual extreme hydrological data from 250 hydrometric stations,the paper studied inter-decadal and inter-annual changes and variations with flooding occurrences in eastern Chinas monsoon area and typical river basins of the Pearl River and the Huai River.On the basis of annual maximum and peak-over-threshold (POT) series data, the authors undertook flood frequency calculations through the P-Ⅲ distribution curve by moving series year by year at an interval of 30-years, diagnosed the change tendency of flood frequency parameters and identified stability of peak discharge series by using Mann-Kendall statistical method.Two periods of 30 years each (1981-2010 and 1951-1980) are compared to analyze the parameter estimates of peak discharge series for the latest 30 years.The study finds that flooding in China features prominent periodic higher and lower flood frequency over the decades, with more drastic increase in recent 3 decades, and higher frequency of regional rainstorms, flash flooding,concurrence of drought and flood as well as their quick transition are becoming more and more prominent.The peak discharge variation process in most hydrometric stations is non-stationary.Compared to the first 3 decades between 1951 and 1980, the latter 30 years between 1981 and 2010 found smaller peak discharge density in a 10-year flood, while local short-duration, intensive rainfalls happened more frequently, and flooding in small-medium rivers increases with higher intensiveness.