Based on evolution economic geography theory, this paper employs entropy index to discuss the effects of urban industry variety & professionalization on urban economies, and uses the industrial statistics of 279 cities at prefecture level or above from 2003 to 2010 to empirically study the effects of agglomeration economy, correlation variety and independence diversification of urban industries on urban economic growth. It arrives at the following conclusions: firstly, as a whole, the variety and professionalization of urban industry agglomeration both can promote urban economic growth, but the role of variety is significantly bigger than the role of professionalization; secondly, not all variety significantly promotes regional economic growth; and correlation variety taking knowledge spillovers as the main influencing mechanism can significantly promote economic growth, but dependence variety taking combination effect as the main influencing mechanism cannot promote or has not yet promoted economic growth. It shows that urban economic development in China benefits from knowledge spillovers resulting from diversification and professionalization sectors with correlation or complementarity. It confirms the important role of correlated but diversified knowledge spillovers in China's urban economy in urban economic growth.