Abstract: The rain rates measured by the TRMM PR and observed by the 430 rain gauges in the southern China from January 1998 to December 2005 are compared in the multitime scale in order to study the difference between these two precipitation datasets. The results suggest a significantly consistent precipitation distribution at the 2.5 degree horizontal resolution with one another in either the multiyear average scale or the multiyear seasonal mean scale but with a certain difference existing in the extreme value and its covering region. Generally, the mean rain rate obtained by rain gauges are relatively higher than that by the PR. The region with the difference less than 1 mm/d occupies over 50% in the southern China while about 30% of the southern China shows the difference of about 1-2 mm/d. Such the difference reaches more than 2 mm/d during the summer in the most part of the southern China. The analysis indicates that the difference between these two datasets is mainly determined by the spatial density of the rain gauges. The correlation coefficient is higher than 0.7 when the number of rain gauges in a grid is over 6. However, both the datasets show less correlation in summer than that in the other seasons, whatever be the number of rain gauges in a grid. The difference between these two is also larger in the region with high frequency of convective precipitation than that with frequent stratiform precipitation. By using the TRMM PR measurements, the distribution of the monthly mean rain rate averaged over the 8 years in the Tibetan Plateau during summer is also investigated in this paper. The results show that there exist 2 mm/d precipitation areas in the eastern plateau in June, while in July and August 1 mm/d rain rate areas cover great part of the plateau (except for the western plateau). And in the center of the plateau a rain rate of over 3 mm/d appears. Time series of monthly rain rate departures show the months of less rainfall are more than those of more rainfall in the plateau.