Grid-Xinanjiang hydrology model used in this study is a spatial grid-data processing model which combines theory of the conceptual Xinanjiang model with different kinds of analysis on DEM, soil type and land cover data. We applied the model in Shuipingkou Reservoir located in the upstream of Yuqiao Basin to study the spatial variation of flood factors and the flood procedure in a semi-humid region. The simulation experiment based on the data ranged from 1978 to 2012, and we analyzed the flood simulations to check the applicability of this model in semi-humid regions. The simulation results turned out to be satisfied that showed significant changes of runoff producing in various areas of the basin, suggesting that the model has the potential in space to be adaptable for the semi-humid regions.