Abstract: The variable features of the heat in the growing period (daily mean temperature ＞10℃ accumulated temperature and its durable days) and the low temperature in the overyearing period (daily minimum temperature ＜0℃ negative accumulated temperature and the extreme minimum temperature＝ in Shanghai, Hefei, Jinhua, Wuhan, Changsha, Nanchang, Ji’an and Hengyang stations are analyzed, respectively. Using the spectrum analysis, the climatic cold or warm variable periodicity and the long-range fluctuation tendency are found over the lower and middle reaches of the Changjiang River, Furthermore, in view of the climatic prediction and forecast, it is shown that the anomalous change of the cold or warm may be a potential threat of establishing a modern agriculture system of high yield, excellent quality and high efficiency in the end of this century. So, in order to construct a new agricultural ecological systems with high control power of climatic change, it is necessary for paying attention to “the climatical input”, surmounting the traditional agricultural experience, and improving the crop cultivation and rotation systems.