Abstract: To investigate the effect of the spatial pattern of urban subsurface on flooding processes at the community scale, eight different spatial patterns of urban subsurface at the community scale are constructed and the corresponding numerical models of urban flooding are established to simulate the flooding processes under six different design rainfall conditions, with recurrence periods ranging from 2 to 100 a. Based on the simulation results, the flooding characteristics, spatial and temporal changes, and hydrodynamic characteristics are analyzed. The results indicate the following: ① The spatial pattern of the urban substrate affects the inundation characteristics, the spatial and temporal variations of inundation, and the distribution of inundation flow rate at the community scale. ② The peak total ponding volume, peak ponding area, and maximum regional ponding depth differ significantly between the spatial patterns of urban substrates for design rainfall return periods of 2 a, 5 a, 50 a, and 100 a, whereas their differences are slight for return periods of 10 a and 20 a. ③ The distribution of higher flow velocities in flooded water is primarily concentrated at road intersections, with the difference in the maximum flow velocity being reflected in 31.9% of the scenarios analyzed. ④ Among the eight different spatial patterns of urban substrates, the circular radial pattern can manage internal flooding more effectively. The result of this study can provide scientific reference for the spatial control of urban subsurface and for investigating the formation mechanism of urban flooding.