The classification of precipitating cloud systems over Thailand was attempted by using cloud radar reflectivity data separated into convective and stratiform clouds based on a reflectivity threshold. A statistical technique is applied to examining the development of small-scale variability of radar reflectivity over the mesoscale storm. The convective cloud generally brings about higher rain rate than the stratiform cloud. After applying the classification method, rainfall estimation by radar was improved by using specific parameters for each rain type. Moreover, the classified results show consistency with TRMM 2A25 product.