Aiming at the increasingly prominent flood problem in cities in China, taking a block in the main urban area of Fuzhou City as an example, a flood simulation model is constructed based on SWMM and InfoWorks ICM. The key parameters of SWMM model are calibrated based on differential evolution algorithm. Under different rainfall scenarios, the inundation and risk distribution of block surface is simulated, and the reliability of simulation results is compared and evaluated. The results showed that the SWMM model parameters were effectively calibrated based on differential evolution algorithm. The errors between simulated and observed water level of two flood peaks were under 1%. Driven by rainfall with return periods of 10a, 20a, 50a, and 100a, the submerged area were 3.14 hm², 3.37 hm², 3.61 hm², and 3.72 hm² respectively. With return period increasing from 10a to 100a, the proportion of total submerged area increased from 27.40% to 32.46%. The simulation method based on the coupling of SWMM and ICM has good applicability in the study area.