Abstract: Whether there is any occurrence of freeze injury to fhe oranges in the region of the Three Gorges of the Changjiang and the Qingjiang valley ("valley region"for short in the following)depends not only on the protective screen of mountains but also on the cause of formation of synoptic climatology. The region is under the control of the southwest warm trough and this is also an important cause for the winter warmth in the valley region.By the alternative method on simplified extreme value of Gumbel distribution, the recurrence period of low-temperature free ze injury in January 1977 in the valley region is at least every 25 years.The cycle of the orange production in Zigui County calculated dy the method of maximum entropy spectrum is a long cycle of about 27 years. Through comparison, the paper points out that our country should make the dest use of the superiority of the climate in this region, and that a large-scale orange production base should be extablished so that resource superiority can be transformed into economic superiority as soon as possible.