In order to improve the validity of forecasting for thunderstorm's intensity, the data of lightning location is used for classification the thunderstorms intensities. The sounding data is used for calculation the 47 convective parameters during June-August from 2008 to 2010. The relationships between the intensity of thunderstorms and 47 convective parameters are analyzed respectively. The convection parameters, which are closely related to thunderstorm's strength, are selected as the forecasting predictors of thunderstorm intensity. On that basis, Logistic regression analysis is adopted to establish a thunderstorm forecasting models. By use of the testing samples, the forecasting model is tested. The result indicates that, the Hedike skill score of Logistic regression analysis is 0.396, and can identify 30% of the severe thunderstorm and 60% of the normal thunderstorm, respectively. It is obvious that Logistic regression has good indicative significance to forecast thunderstorm potential intensity.