[Objective] Refined survey and mapping data were used to simulate urban rainfall and runoff processes in order to activate land resource data assets and to promote precise urban flood risk management and control.[Methods] The study was conducted in the Panyu District of Guangzhou City. The SCS-CN runoff model and GIS technology were used to simulate the depth of urban flood inundation under different intensity rainstorm situations on the basis of high-precision topographic and architectural data in order to quantitatively analyze the characteristics of inundation risk in the study area. Additionally, a loss experience model of disaster-bearing bodies was used to assess flood loss risk and to identify highly vulnerable areas.[Results] ① The flood inundation risk area in Panyu District was spatially clustered with rivers and low-lying urban areas, and the streets and towns near the Shiqiao-Shawan watershed and the Sanzhixiang-Dashi watershed had higher inundation risks. ② Agricultural land and construction land were expected to be most severely affected as the intensities of rainstorms increased. ③ For the case of a 100-year rainstorm, four planning management units in Panyu District were at high risk of loss, and their losses mainly came from residential buildings, while the units facing medium risk of loss were mainly associated with agricultural land inundation.[Conclusion] Refined survey and mapping data can effectively identify the distribution of high loss areas that are prone to potential inundation. These results are in line with the actual situation. The study results can provide advance research and planning support for urban flood control and sponge city development and construction.