In year, The observation of 10 sorts of corn hybrids with different maturing dates called early, medium and late corns and with their different leaf angles such as erectophile and planophile have been taken in Beijing, Yanqing County (Beijing area), Taian (Shandong Province) , GongZhuling (Jilin Province) and Shihezi(Xinjiang Aitononous Region), Based on the data obtained from the observations,a normal growing function was derived on the princplie laws of th accumulated dry matterW=[1+e^{8.56-13.52μ)<.sup>]-1In accordance with the function, the authors built up a model of the potentiol maximum biomass dependent on the accumulated temperature. B_max/kg·-1=100+1.1∑T_m. The model was applied to estimate the potential corn yield of the hybrids different maturing and the results in assessing the impact of climatic change are discussed.}