Based on the 1951-1980 climatic data of about 500 stations and a wealth of the agro-climatic information, a summary of the agroclimatic regionalization of China is given in this paper. This regionalization is made up of three levels.The first level, there are three main agroclimatic areas. The east monsoon main area, humid and subhumid, with tolerable and plentyiful rainfall in the warm period, has good climatic productive potentiality. In the northwest main area, water deficit greatly himders the function of light and heat factors. Its southern boundary is set by the 50% frequency line of the annual precipitation ≥ 400mm, with number of days of gale wind as a subsidiary index. In the Qinghai-Xizang Plateau main area, the heat insufficiency hampers the full utilization of the light-water resources. The accumulated temperature (above 0℃) of 3000℃ and the warmest monthly mean temperature of 18℃ are taken together as the boundary of this area.The second level: Fifteen agroclimatic zones are delineated based on the heat demand of the cropping systems and main crops. The east monsoon main area, is divided into ten agroclimatic zones using mean annual lowest temperature and the accumulated temperature above 0℃ as the criterions. In the northwest main area, the accumuluted temperature above 0℃ is used as index. There are two zones, i. e. the arid middle temperate zone and the arid south temperate zone. In the Qinghai-Xizang Plateau main area, ∑t( ≥ 0℃) and the temperature of the warmest month are taken as criterions for delineation. On this basis, Qinghai-Xizang Plateau is divided into three agroclimatic zones, i. e. plateau temperate zone, plateau subfrigid zone and plateau frigid zone.The third level reflects agroclimatic types. Based on regional agroclimatic features, with emphasis on moisture condition and agroclimatic calamity, fifty-five agroclimatic regions arc delineated (see Fig. and Tab.).