The same period of rainfall and heat is a prominent feature of China's climate, and the rainfall is the most abundant at the hottest time. This kind of climate provides a very favorable natural environment for the development of agriculture and breeds Chinese civilization, however, the drought and flood disasters caused by abrupt climate change seriously restrict the economic and social development.

From ancient times, the Chinese have struggled with droughts and floods, the frequent alternating floods and droughts have always been the main disasters facing our country.

We find that in this period of history, which is the closest to the contemporary society and also the most violent social change, no matter how many changes the social form has undergone, drought and flood have more or less affected the Chinese civilization, for example, Dynasty change, population migration, economic and social development, etc. Drought and waterlogging are still important natural disasters that we cannot avoid.

China has a complex landform with a large span and uneven seasonal distribution of annual precipitation, the rainy season is concentrated from May to October, and the precipitation in these months generally accounts for about 80% of the total precipitation of the whole year, and the amount of the precipitation will basically determine the drought and flood situation of the year.