Based on the data of the Drought/Flood in the northwest, the north, and the east of China for the last 530 years, the abrupt change and the periodicity of the Drought/Flood series are analyzed. The results indicate that there is a period of 22-year and 169-year respectively in Shaanxi and an obvious abrupt change in Shaanxi in 1645,which is earlier about 6～7 years than North China, about 40～50 years than East of China. There is some periodicity characters of precipitation in Shaanxi and East China in recent 5 decades, and the variation is different. The dry and warm climate will continue to 2010s in northern Shaanxi, this is the facts that the ecosystem managing project must be faced.