Abstract: Precipitation estimation of automatic meteorological stations was achieved and historical data were extended by using theory and method of disaster risk formation and analyzing the precipitation data of basic meteorological stations from 1961 to 2011 in Wanquan River, and spatial distribution of hazard was obtained with trend surface and residual method, and the disaster risk was regionalized by selecting spatial indexes which were appropriate for evaluating sensitivity, vulnerability and ability of disaster prevention and reduction with storm and flood disaster in small watershed. The results indicated that western hazard was higher than east, and most of areas in eastern Wanquan River were located regions with risk that was above the average. On the contrary, the risk of west regions was lower than the east. The risk of some areas which center on Jiaji County was highest, and so do the towns of Lingkou, Hanlin and Dalu in the north of watershed.