A study of the rule about the heavy rainfall is investigated using the 500 hPa-signal field. The climate signals have been extracted from 500 hPa constant level chart. They are extracted from the day of the heavy rainfall and two proceeding days. The synoptic diagnosis in the signal field can be ana- lyzed. The rule about occurrence of the heavy rainfall and the anomaly climate signal in signal field also is revealed in apomaly climate background. It can be found that the significant signal area with negati...