Abstract: A two-dimensional hydrodynamic model using a TVD finite volume method and unstructured triangular mesh is presented for prediction of the routing of overbank floods over complex floodplain topography. This model has been verified against the previously reported experimental data of dam-break flows in a laboratory flume, and a favourable agreement was achieved between the model predictions and measurements. We applied the verified model to an overbank flood event on a typical floodplain of the Lower Yellow River, and examined in detail the effects of mesh scale and village region roughness on the predictions. The results show that these two factors have influences of different degrees. Smaller mesh scales cannot achieve better results, but reasonable scales should be those that conform to the density of bed elevation points measured. Predictions of flood inundation by using center-hollowed village regions and different village roughness values were significantly different. In the center-hollowed case, an increase of up to 0.57 m in the maximum water depth was calculated, relative to the roughness modelling. An increase in village roughness from 0.06 to 0.12 caused an increase of 0.25 m in the maximum water depth and a reduction of 0.24 m/s in the flow velocity. Thus, in practical engineering applications, conceptualization and modelling of village regions and their roughness values should be determined according to real conditions.