Estimating Agglomeration Economic Effect Based on Infrastructure Factors ——An Empirical Study Based on China's Regional Dynamic Panel Data at Prefectural Level

Based on China's prefectural panel data,this paper tests the function of infrastructure and agglomeration economy on productivity differences in China' s cities by using the framework of new economic geography. The results show that non-agricultural employment density has threshold effects on non-agricultural labor productivity. When the density of urban non-agricultural employment is higher than the threshold,it has significant positive effect on urban non-agricultural productivity. However,the threshold is higher without considering infrastructure factors, which means infrastructure plays a positive role in the formation of agglomeration economies. Besides,research also finds out that agglomeration economy is more significant in big cities.