Based on the typhoon precipitation data from seven stations in Hangzhou City during the period from 1960 to 2009 and combined with the society economic and natural geographic factors, this study builds a set of typhoon rainstorm flooding disaster assessment model including hazard factors, hazard inducing environment, hazardaffected body and disaster prevention ability. And a map of Hangzhou’s typhoon rainstorm flooding disaster risk division was drawn using 100 m × 100 m raster as basic assessment unit, by means of GIS spatial analysis technique for rasterizing evaluation indices and fuzzy comprehensive assessment methods. Finally, the five risk zones of Hangzhou, i.e. higher risk, subhigh risk, medium risk, inferior risk and lower risk, were mapped. Results show that the typhoon rainstorm flooding disaster risk in Hangzhou has an increasing tendency from southwest to northeast. The coastal plain, involved with Xiaoshan District, Yuhang City, main urban area of Hangzhou, and so on, has relative high risk, while the midwest mountain and hilly area, involved with Jiande City, Chun’an County, and so on, has slightly lower risk.