Hainan is the biggest tropical region and the biggest natural winter green house of China.There are rich light and warmth resources and seldom typhoon, rainstorm, and plant diseases and insect pests. In the special dry time, winter crops can normally grow under suitable irrigation and their yields are also stable and high. The varieties of the melon, vegtable, grain and forage crops that can be planted in winter are rich. The area that can be used in winter is very large. It is the key measure that the winter agriculture is actively developed by using the winter superiority to realize high-quality and efficient agriculture. For in summer typhoon,floods and plant diseases and insect pests are all serious, the potentiatity of the resoures development is limited and the products of tropical crops are facing keen competition from some countries of southeast Asia, south Asia and America.