The refined quantitative evaluation of precipitation process intensity is one of the important requirements in the modernization of meteorological operational services and a key link in the rainstorm disaster impact assessment research. By using rainfall observation data from 2410 weather stations since 1961 and precipitation background at stations to represent the regional characteristics, the beginning and end conditions of a single station and regional precipitation process are defined, and three evaluation indexes of precipitation process are extracted, including rainfall intensity, duration and range. In addition, three evaluation indexes in the process of precipitation are calculated based on the spatiotemporal precipitation data. Then, based on percentile distribution and probability statistics, the three evaluation indexes of precipitation process are subdivided and the comprehensive intensity evaluation model of precipitation process is established. Finally, the intensities of precipitation process are divided into five grades including extreme, extrasevere, severe, heavy, medium grades. The results of validating the evaluation method show that single station and regional precipitation intensity grade evaluation method is reasonable. It can not only reflect geographical features, but also characterize the effect of the precipitation process. This method has strong the maneuverability, and can be directly applied to meteorological service operations and heavy rain impact assessment. It can also be used for the storage of historic precipitation process case, providing basis for the characteristics analysis of disaster information.