Nushan Lake, lying at the juncture of the middle and lower reaches of the Huaihe River, belongs to Chihe River system, a branch of the Huaihe River. It is of great significance to study a long-term fluctuation of precipitation, drought and flood in the transition area between north sub-tropical zone and south temperate zone. Since Northern Song Dynasty the area around Nushan Lake is one of the regions which frequently suffer drought-flood hazards, especially flood hazards. Historical records show that since A. D. 960 drought-flood disasters happened in 747 years, almost two disasters in three years. 57% of them, 425 years, were floody, and 43% of them, 332 years, were droughty. Millenary drought-flood series in the area has been constructed on the basn of yearly identification of historical records. It has been concluded from the series that the past thousand years can be divided into two periods, each with fluctuation of drought and flood. It was dominated by drought from A. D. 960 to A. D. 1370 and by wet or flood from A. D. 1371 to A. D. 1910. Fitting and extrapolation were made based on analysis of the periodicity of the series. It has been predicted that it may incline to wet in the 2010s, and to drought from the 2010s to the 2030s in the area.