Based on the data of meteorology and crop yield in 7 regions of China from 1961 to 1990,the method of entropy analysis in information theory is applied to discussion of the temporal and spatial distribution patterns of the entropy change of 4 meteorological factors (mean temperature, maximal temperature, minimal temperature and rainfall) in recent 30 years. The unsteadiness of climate change in China is analyzed in detail. After that,the relationship between climate fluctuation and agrometeorological disasters and the impacts of climate fluctuation on crop yield are revealed qualitatively. The regression models of yield and entropy of meteorological factors in different regions are established.