Abstract: The accurate prediction of crop developmental stage is the basis of the agrometeorological condition assessment and disaster monitoring and early warning. The observed data including summer maize development stage and weather data from 1981 to 2006 of 19 agrometeorological stations in Henan province were used to establish the comprehensive climate suitability model of summer maize. And further, the physiological index and prediction model for developmental stage of summer maize were constructed based on the comprehensive climate suitability model. The prediction model was validated using the observed data of 4 years from 2007 to 2010. The results showed that there was good agreement between observations and predictions for the duration of each developmental stage. The correlation coefficients between observations and predictions of different stages were statistically significant at level P<0.01,except for the stage of tasseling to milk ripeness, which was statistically significant at level P<0.05. The absolute error (ABSE) ranged between 1.8 and 2.9 days, and the standard error (RMSE) ranged between 2.8 and 3.9 days. The accuracy was highest for the stage of 7 leaf-jointing and lowest for the stage of milk ripeness to maturity. The accuracy of the prediction model can basically meet the needs of agrometeorological operation and services

Key words: Climatic suitability, Developmental stages, Prediction model, Summer maize