The hourly emerged precipitation products, derived from the hourly precipitation observations by national meteorological observing stations in China and CMORPH (Climate Prediction Center MORPHing technique) data, as well as the reanalysis data of the European Centre for Medium-Range Weather Forecasts (ECMWF) are used to study the diurnal variation characteristics of the summer precipitation on the Qinghai-Tibet Plateau. The results are shown below. The diurnal variations of the summer precipitation and precipitation frequency over the Qinghai-Tibet Plateau show that the peak occurs at nightfall and the valley at noon. The diurnal variations of the summer precipitation in the northern and southern regions of the Qinghai-Tibet Plateau are different in that the diurnal variations in the southern region are the same as the diurnal variations of the total precipitation on the plateau, while the precipitation in the northern region shows its peak in the morning and the valley in the early morning. In terms of the duration of precipitation, short-term rainfall occurs more frequently than long-term rainfall, but about 70% of the total precipitation comes from long-term rainfall. Due to the features of valley landform and altitude distribution, the summer night rain rate on the Qinghai-Tibet Plateau is high in the middle and low in the northern and southern regions. The intensity variations of the wind field and divergence field over the Qinghai-Tibet Plateau correspond to the precipitation occurrence region and intensity. Therefore, the changes in the divergence may be one of the important reason for the changes in the precipitation intensity in the Qinghai-Tibet Plateau.