Abstract: In order to strengthen the forecasting ability of short time heavy rainfall, this paper uses L band radar detection data in Tengchong of 20082009 and precipitation data in Baoshan City to examine the relationship between precipitation and SI, LI, t-td during the day and night.It has been found that the intensity of precipitation was negatively correlated with t-td and SI, and positively correlated with LI.Using correlation and significance test method applied to determine the numerical value of 6 kinds of prediction factors and combination of forecasting factors into 8 kinds of forecasting methods.After comparison, in light of the forecast method of Baoshan City during the day or at night, the forecasting ability of the method of heavy rainfall data in Baoshan City during 20102014 has been tested.The correct rate during the day and night is 56.00% and 60.00%.Inspection certificates, this method is of a gtreat value as for the disaster weather forecast.