With the need in the new forecasting operation process,by virtue of the similarity between the HLAFS products in MICAPS platform and the three-dimensional space physics field relative to the initial,development and extinction of the heavy rain,a prediction of the on/off region heavy rain is made under complex examination and analysis which is based on the magnitude interpretation and application. The programming, automation and objectivity are realized in the whole process. Based on the mean field distance of the two types of weather process,the heavy rain prediction with the analog discriminatory analysis results is made. The examing results are reasonable, the mean TS during May-September,1999-2002 is more than 33%.