Based on published rice yield-weather models for different cropping types in various areas of China,the obtained data fall into three classes according to double-harvest early rice,double-harvest late rice and single-harvest rice.Forecasting factors are extracted and quatita tively processed,from which rice is regionalized using clustering method as four zones for double-harvest early,two for double-harvest late and 9 for single-harvest.The primary and secondary affecting factors and their affecting perio ds are discussed,which may provide scientific basis for large-area rice field prediction.