The cloud top temperature data （TBB） and radar data from Hefei, Wuhan and Changsha are used to estimate the precipitation of a rainstorm event occurred on 8 July 2003. The result shows that the joint estimation method can describe this event well; the satellite data makes up the lack of radar data on space distribution; but the satellite estimation underrates the intensity of extraordinary heavy rainfall (daily precipitation greater than 200 mm) while overrates that of moderate intensity rainfall. When the radar data are combined with satellite data, the estimation result can express well the mesoscale structure features of the rainstorm cloud cluster, and the estimated precipitation field can reveal the spacetime distribution features of the severe ainfall event.