In China, there are large geographical spans of east -west and north -South and obvious difference of hydrologicalcharacteristics. This paper analyzed the hydrological characteristics of climate, rainfall and runoff, rainstorm and flood in the sevenmajor river basins, and summarized the spatial distribution of rainfall and runoff in the upstream-downstream and mainstreamtributary,and also studied the causes, occurrence time, spatial distribution, rainstorm intensity, flood process and flood encounter ofthe annual and inner-annual distribution of rainstorm and flood.