The National Centers for Environmental Prediction (NCEP) Regional Spectral Model (RSM) was used to simulate 20-year (1984-2003) summer precipitation over East China with high horizontal resolution of 30 km, moreover, the climatology, interannual variability, daily variation and extreme events found from simulation was tested and the atmospheric circulation characteristics causing precipitation deviation was analyzed. Results show that the spatial distribution, time variability and precipitation amount of summer rainfall simulated by RSM are similar to the observation, and basically present interannual variability distribution of summer precipitation, however, the simulated rain belt extended more to south and developed weaker than the observed one. Daily precipitation variation simulated by RSM was similar to the observation, representing the features that concentrated in the south and east and simulating the feature that daily rainfall in June over Jianghuai area jumped northward with time. The day number of different precipitation intensities in the simulation are generally consistent with the observation result, but the maximum centers of the simulation extended more to north compared with observation. The distribution of observed and simulated extreme precipitation indexes is similar. In conclusion, the RSM can be used to investigate the precipitation characteristics over the eastern China well.