Abstract: To reduce the losses induced by urban flood hazards, it is necessary to research urban flooding via numerical modeling and to obtain accurate and reliable flood information in advance. According to the hydrological and hydrodynamic theories and methods in urban flood research, a specific method for the coupling of one-and two-dimensional models is proposed in the present work. An integrated hydrological and hydrodynamic model is constructed via horizontal and vertical connections based on the Storm Water Management Model (SWMM) and a self-developed two-dimensional model. This research also proposes a novel coupling strategy for one-and two-dimensional models based on a dynamic-link library. The coupled model is verified by both theoretical and practical case studies. Taking the vertical connection problem as the theoretical case study, the correctness of the model was proven by comparing the model results with InfoWorks ICM software. To verify the flood modeling capacity of the model in watershed-scale areas, the Donghaochong Basin in Guangzhou was taken as another case study. The modeled results were found to be in line with the measured data under two historical rainfalls, which indicates that the model exhibited good precision and reliability in both pipe flow and surface flow simulations. In summary, the proposed coupling method is both reasonable and feasible, and the integrated hydrological and hydrodynamic model is reliable and of significant application value.