Abstract: Watershed flood simulation for urban areas is important for river safety and flood control, but it is a difficult issue due to its complicated factors. Based on a one-dimensional MIKE11 model, we integrated on the model platform the processes of runoff generation in impervious areas, multi water projects control, regional drainage, and tributaries confluence, and constructed a coupled modeling system of Qinghe watershed flood in the urban area of Beijing. The river and floodgates hydraulic parameters are validated with design flood volume and its corresponding water level data of 20 year and 50 year return periods. And the floodgates operating rules are validated with the water level data from the storm and flood events in July 21 in 2012. The simulations shown a good agreement with the water level, total flood volume, and peak value monitored at eight floodgates. Application of this model to different scenarios of design storms shows that low water level corresponds to relative high flood volume and the river can undertake flood volume of 20 year rainfall return period. The riverbank in the middle reach between the floodgates of Qinghe and Yangfang is the most serious area for flood control. For the rainfall return periods from 1 year to 20 year, the ratio of final volume of storm water into the river over the river storage capacity is in the range from 33.5% to 54%. This study would supply a guide to flood control and storm water utilization assessment in the watershed of urban area.