Abstract: According to historical records,there are 264 drought and flood years, occurred in the upper and middle reaches of the Changjiang River during last 1020 years from 961 to 1980.The evolutionary law and developing trend of drought and flood years are studied.The distribution of drought and flood years are non-uniform and the dry and flood seasons in a year are concentrated.At the angle of monsoon circulation,at present the climate in the upper and middle reaches of the Changjiang River is just in the late stage of frequent drought period and the early stage of least flood period.In addition,the cycle of drought and flood and the feature of drought and flood occurred in the upper,middle and lower reaches of the Changjiang River are analyzed.It shows that the short period less than 10 years is in the majority,and the drought and flood occrred most frequently in the middle and lower reaches of the Changjiang River.