In recent years, urban pluvial flood have significantly increased because the rain storm cannot be fully assimilated by a city’s drainage system. Climate change and rapid urbanization have contributed significantly to the increase in flood risk. To mitigate floods, low impact development (LID) technologies are sustainable drainage solutions for urban storm water management. This study aims to choose the optimal LID design through twelve scenarios consisting of permeable pavement (PP) and green roof (GR) in different proportions. The optimal scenario is the one that can minimize the peak flow and the runoff volume with the lowest budget. The Storm Water Management Model (SWMM) and cost-effectiveness (CE) method are used to assess the hydrological performance and economic benefit of different designs of LID practices in urban area.