Taking the annual and monthly maximum one-hour precipitation intensity and its occurrence time as indexes, the temporal and spatial variation characteristics of the maximum one-hour precipitation in the Three Gorges Reservoir (TGRR) from 1998 to 2020 were explored by using the trend test, period analysis, empirical orthogonal function and comprehensive intensity assessment of precipitation process. The results show that the occurrence time of the maximum one-hour precipitation in the reservoir area moves to the pre-flood period every 10 years, and the maximum one-hour precipitation intensity in the main flood season in July has an 8-year cycle. Compared with that before 2010, the heavy precipitation area in the reservoir area shows a trend of migration from the upstream to the dam site after 2010. The maximum precipitation intensity of one hour is close, but the precipitation process with long duration and wide coverage has higher comprehensive intensity and has more impact on flood control safety.