To enhance the risk assessment of rainstorm-flood disasters in Sanming City, an integrated approach combining fuzzy analytic hierarchy process and principal component analysis was developed to determine the coefficients in the index system. High-resolution satellite imagery was used to interpret the distribution of impervious surfaces and cultivated land, along with other socio-geo-economic data, to map the risk distribution of rainstorm-flood disasters in Sanming. The results revealed that the impact of rainstorm-flood disasters in Sanming City tends to decrease from north to south, and that the increase in urban impervious surfaces exacerbates the risk of flooding. Future urban planning efforts can take into consideration the risk of rainstorm-flood disasters to mitigate the impact of meteorological hazards on the city.