In recent decades,in the context of global warming and rapid urbanization,increasing flood and waterlogging have resulted in a great threat to urban socio-economic development and public safety,and have been one of the hotpots in the field of natural hazards research.In this paper,the city center (within outer ring) of Shanghai,China has been selected as the study area.A simplified 1D/2D hydrodynamic model (FloodMap) was used to derive fluvial flood inundation associated with urban road network.Furthermore,GIS-based network analysis (New Service Area and New Closest Facility) was applied to evaluate the emergency responses accessibility of critical public service sectors (Public Safety 110) under normal and multiple scenarios of fluvial flooding (current state,2030s and 2050s).The results show that,1) at normal (smooth traffic) condition,emergency response service could cover almost the total research area,which could reach the majority (80%) of the study area within 15 minutes at the condition of extremely congested roads.2) During 1 in 100 year flood scenario,part of the road network (mainly at the bank of Huangpu River) loses its capacity.As the interruption of the surrounding road network,the number of public security agency which lost the emergency response capability has also increased significantly.Among these,the most serious condition is of 22 police stations who lost emergency rescue capability,while the service area of emergency department have obviously decreased.3) During 1 in 1000 year flood scenario,the response areas were further reduced than normal and about 1/6 of the public security organization lose their emergency response ability.Under the condition of traffic congestion,30% of the central city couldn't get emergency rescue.To conclude:in the flood situation,fluvial flooding have a serious influence on urban road network,leading to travel delays and disruption of emergency vehicles,along with emergency service,whose geographic coverage is smaller than normal.As the high vulnerability areas (shanty towns) mainly located in the Huangpu River floodplain,emergency response for some parts of this zone will be delay and even unreachable.The study suggests that the assessment of urban police(110) emergency response under fluvial flooding scenarios are proved to be practical,and will provide theoretical and scientific basis for formulating prevention and response measures.