Abstract: Based on the meteorological data from 1953 to 2005 in 48 weather stations in the grain production area of the eastern Inner Mongolia,the grain production area could be divided into different parts in terms of climatic analogy by hierarchical cluster analysis and correlation analysis.Water and heat changes were of an obvious regional consistency.Using the average temperature,precipitation and sunshine duration as time series of heat,water and light,the characteristics of climate elements and their effects on agricultural production were analyzed.The results indicate that temperature has an increasing trend in each region.The tendency rate is 0.3—0.4 ℃/10 a,which is higher than that in China (0.22 ℃/10 a).Warming tendency is increasing from the western to the eastern in Inner Mongolia,and average minimum air temperature increases obviously.The relationship between the warming amplitude of average maximum air temperature and elevation is positive.Warming tendency is obvious,especially after 1988.Precipitation has a decreasing trend and its inter-decadal changes fluctuate greatly.Precipitation of growing season in the grain production of the eastern Inner Mongolia decreases obviously and air temperature increases rapidly,so warming-drying trend is obvious.Furthermore,water and heat matching pattern is changed with the decreases of temperature difference and sunshine duration.Consequently,food yield might reduce in the future.