Based on the principle of energy balance and the Talling's equation about calculation of daily photosynthetic productivity, a methods for simulant esti-mation of the yearly photosynthetic productivity and the climatic productivity were proposed. Considering the general features of lakes in China,the seasonal variation of photosynthetic productivity and the geographical distribution‘climatic preductivity were estimated theoretically in 36 water bodies of eastern China, The climatic productivity decreased from south to north. This tendency has related cla-sely with the phatnsynthetically active radiation in the atmosphere,the actual sun-shine duration per year as well as the seasonal and spatial variation of water tem-peratura. Except the northern part Qf the north-east China, the climatic producti-vities in the eastern China rangBd from 1.6 to 24.q},C}mn·yr., which is equiva-lent approximately to the phytoplanton productivity of oligotrophic lakes with si-milar climate in the world. The major reason of low climatic productivity in north-east China is the short growing season. By the way, the major reason of low climate productivity in the basin of Sichuan Province is the lower photosynthetic praduc-tivity in the summer and autumn.