The particularity of geo-environment in the mountain cities of Southwest China,which are suffering frequent flooding and serious damages,makes great difference to the pattern of engineered prevention and control of urban flood from those of non-mountain cities. By examining hydrological observations for recent 10 years collected in a typical mountain city, Chongqing, this research tried to make a causal connection for the formation and development of urban flood to the features of urban hydrological processes by integrated analysis. In consideration of the properties of mountain cities, such as diversity of mountain watersheds, grouping of urban spaces and multi-dimen-sionality of local communities, etc.,it commenced with the theory of water circulation to conduct hydrological process modeling on multi-scale basis, and accomplish a construction of framework of integrated control of flooding in mountain city:(1) Construction of ecological security system on a watershed scale; (2) Infrastructure layout and space optimization of flood control on a urban scale; (3) Design of facilities with against flooding damages on a community scale. The investigation on the governing mechanism of urban flood and resultant scientific merits would provide reference to rainfall flood control in mountain cities under the circumstance of global warming trend.