本文应用负积温（日最低气温＜0℃）≤–90 ℃和极端最低气温≤–8 ℃作为柑桔严重冻害指标。计算了不同寒潮路径、强度和极端最低气温的空间分布与柑桔冻害关系。运用谱分析方法，提出引起长江流域柑桔严重冻害的负积累和极端最低气温出现周期的地区差异大；同时，预测到本世纪末，长江中、下游地区柑桔生产中存在着严重的冻害，平原地区更为严重。因此，柑桔栽培应充分利用山体、水域效应，选择暖区、暖带地段建立桔园，不要强求连片种植，更不宜强调建立柑桔种植带。
In this paper, the negative accumulated temperature (daily minimum temperature < 0oC) ≤-90oC and the extreme minimum temperature ≤8oC are used as the orange heavy freeze injury index. The relationship between the orange freeze injury and different cold wave paths, intensity and spatial distribution of the extreme minimum temperature are calculated. Using the spectrum analysis, it is found that there are the period lengths of 9—10 and 3—6 years of orange heavy freeze injury caused by the negative accumulated temperature and the extreme minimum temperature in Yangtze river valley, and their regional difference is bigger. Furthermore, the forecasting for the heavy freeze injury of orange and making proposals for the orange culture have been done.