he grain yield per unit area sown in China has been increasing from 1949 to 1992, with an annual fluctuation which, besides some policy influences, was mainly resulted from the annually climatic variations, because of the monsoon climate characterized by annually considerable variation mainly in the temperature and rainfall and various na tural disasters such as floods and draughtThe law of temporal and spatial variation of climatic yield which is determined by the three natural factors including light,temperature and precipitation, was analyzed in this paper. It showed that the years with lower grain output per unit area are identified with the years of severe natural disasters. The per unit area yield of grain in the eastern China is higher and more fluctuating than that in the western region. Stabilizing the grain yield in the east and increasing the grain output in the west are of the major options in terms of strategy. The result of EOF analysis indicated that regional unanimity of climatic yield variation is a main spatial pattern besides the other spatial patterns of north south difference and east west variation in some years. From the temporal point of view, the climates in 1950's and 1980's are good for the grain production.