用≥１０℃积温并结合最热、最冷月均温与极端低温将哀牢山脉北段划分为５个山地气候带、６个山地农业气候层，各带（层）的上限高度背风东坡比迎风西坡提高５０－２００ｍ。因夏凉等限制，喜温作物种植的山地高度（气候）带比东部水平气候带明显降低，农业熟制也相应减少。

The Ailao Mountains lie in the middle part of Yunnan Province, and have a NNW-SSE strike which is almost perpendicular to the wind direction of the southwest monsoon. Researches on their climatic effects are very conspicuous. In this paper, the climatic data measured and the agricultural experiences investigated on the spot at different altitudes on the windward(SW)and leeward(NE)slopes in the northern part of the Ailao Mountains area are used as a basis for discussing the division of climatic belts of this area and the difference in agricultural characteristics between this area and the plain area of East China.①The northern part of the Ailao Mountains area is divided into five mountain climatic belts(from the mountain south subtropics to the mountain middle temperate zone)and six mountain argo-climatic strata according to the accumulated temperature of≥10℃, the hottest and coldest month temperatures,the extreme minimum temperature and the plant indicators. The upper-limit altitudes of various belts(strata)are 50m to 200m higher on the leeward slope than on the windward slope. This difference is increasing with the enhancement of the foehn effect toward the mountain foot.The utilization of agroclimatic resources and some noteworthy problems of agricultural production of the various belts(strata)on the two slopes are discussed in detail.②Compared with the plain area of East China, the climatic of the Ailao Mountains area is clearly characterized by warm winter and cool summer.Owing to the limit of cool summer, the mountain altitudinal belt where the thermophilic crops are planted is 2 to 3 climatic belts lower in comparison with the corresponding horizonal belt in the plain area of East China. In the same climatic belt, the agricultural cropping system of the plain area of East China generally has one more harvest within two years than that of the Ailao Mountain area. The differences of vegetation in the same belt of the mountain and the plain are also discussed.