Abstract: Based on the spatial panel data from 2005 to 2014, taking 26 cities of Yangtze River Delta as the research unit, adopt the Global Moran’s I and Moran scatter plot to test and analyze the spatial autocorrelation and cluster characteristics of city innovation output in the Yangtze River Delta Urban Agglomeration, and build the Standard panel model and Spatial econometric model to make positive researches on the effects and mechanism of spillover effects of city innovation output in the Yangtze River Delta Urban Agglomeration. The results show that: 1) The city innovation output of Yangtze River Delta Urban Agglomeration shows a significant positive spatial autocorrelation and an obvious spatial agglomeration characteristics, formed an agglomeration pattern which takes Shanghai as the core and takes Hangzhou, Nanjing, Hefei and Ningbo as important fulcrums, and this pattern diffused from coastal areas to the inland. 2) The city innovation output of the Yangtze River Delta Urban Agglomeration has a significant positive spatial spillover effect in the geographical space, the increase of innovation output in neighboring cities will promote the innovation capability of the city. 3)The spatial effect has a significant effect on urban agglomeration and innovation output,ignoring the influences of spatial effect on the city innovation output will lead to the deviation of the estimation result. 4)The innovation elements have different effects on the urban agglomeration city innovation output, human capital,investment level and innovation platform can not only improve the innovation level of the city and the neighboring city, but also have significant effect on the innovation and development of city group; The level of economic development and foreign exchange ability of the learning have an obviously positive effect on the city innovation output, but have an obviously negative spillover effects on neighboring city, and have not significant effect on the city group of innovation output; Government support has a promoting effect on the city innovation output, no significant effect on the adjacent city of innovation output, weak effect on the city group innovation output. Finally, the paper puts forward some policy suggestions to improve the urban innovation and development level of the Yangtze River Delta Urban Agglomeration and the directions in the future research.
Key words：city innovation output; spatial agglomeration; spatial spillover; spatial econometric model;  Yangtze River Delta urban agglomeration