Abstract: In order to improve rainfall-runoff simulations in urban area and enhance the details of digitalized urban area with complicated land-surface characteristics,this study selected the core district of Yizhuang Economic Development Zone in Beijing as the study area,and the methodology of sub-catchment division,generalization of drainage pipe networks,and identification of outfall drainage wells was proposed for large-scale urban regions larger than 10 km² with complicated land-surface characteristics,in which local geographical properties,regional waterlogging characteristics,and critical information such as digital elevation model,drainage pipeline networks,and land-use types were considered. This study provides technical support for the researches on rainfall-runoff simulation and disaster warning in urban areas where pipeline-flow observations are sparse in China.