Based on the ingredients-based methodology,a parameter I_ZH,which serves as an indicator of heavy precipitation potential,is designed.Based on the historical data,the relationship between I_ZH and precipitation is obtained.I_ZH may be first predicted by using NCAR/PENS MM5 model,and then the area and intensity of precipitation determined.The positive I_ZH area indicates the rain area and the I_ZH value the precipitation intensity.I_ZH as a composite parameter is a better indicator for precipitation than other single physical parameter indicators.