In order to achieve a high-speed and precise flood simulation, this study took the drainage system of A district in R city of Denmark as research object to construct and compare dual one-dimensional (1D/1D) drainage model by combining GIS-based spatial modeling technology and SWMM-based hydrodynamic coupling technology, and coupled one-dimensional pipe model and two-dimensional flood (1D/2D) drainage model based on MIKE URBAN. Then the flood simulation, evaluation and comparison on the drainage system of the study area were conducted. The modeling process, simulation accuracy and computational efficiency were studied to describe the characteristic and applicable conditions of the above two models. The results showed that the 1D/1D drainage model can realize the extended analysis of surface inundation with high stability and high calculation speed, and achieve high accuracy at low reappearance period, which is suitable for the circumstances of large-scale, emergency management and relatively lower simulation accuracy. The 1D/2D drainage model can realize two-way flow calculation of surface accumulated water with good accuracy, but the information processing and calculation time are long, which is suitable for the circumstances of relatively better computing environment and higher simulation precision. The research results will provide a scientific basis for flood simulation of different scenarios and scales.