Over the Tibetan Plateau, solar heating often produces strong convective instability in the atmosphere. Using 3 years (1998--2000) of Tropical Rainfall Measuring Mission (TRMM) precipitation radar data, our investigations revealed a tower mast shape of precipitation over the Plateau in both height-longitude and height-latitude cross-sections. High rain rate center over the Plateau is located above 6km as a tower penetrating into the mid-troposphere against the nearby background, implying a unique latent heating source injecting directly to the middle atmosphere. Results indicate that there are more isolated rain cells over the Plateau than its nearby regions, and the strongest diurnal cycle of rainfall existing over the Plateau with a peak around 1600 and a valley around 0500 local time, indicating the dominance of convective clouds caused by solar heating. It is also found that the TRMM algorithm might have misclassified weak convections as stratiform rains.