【Abstract】 The urban development is under the effect of various of “catalyst”. The main effect of catalyst is that the new elements improve its surrounding elements; catalyst can enhance the value of existing urban elements or do the favourable conversion. The goal of each catalyst reaction is to create a reaction beyond the sum of individual elements’reaction and imagine a city as a whole rather than the sum of isolated fragments. This paper adopts a method combine of theoretical researchs and analysis of examples,and select the effect of the Hangzhou Bay Bridge construction on Ningbo city's economic development, transportation systems, space structures, and other aspects to research, introduce the "urban catalyst" theory to explain the relatively independent urban development Projects on the overall structure of the future urban development.The aim is to enable the town planners and urban development policy-makers to be consciously thinking of the potential impact of individual urban construction projects and their implementation strategy on its surrounding environment, which could maximize the use of Advantages and promote the whole quality improvement of the urban environment.
【Key words】the urban catalyst the Hangzhou Bay Bridge Impact studies urban construction