As a crucial indicator of modernization, urbanization has significant effects on carbon dioxide emissions. Using a panel data of 141 countries over the period of 1961-2011, this paper analyzes the impact of urbanization on carbon dioxide emissions empirically. We employ two-way fixed effects model based on the extended STIRPAT theoretical frameworks. Our results show that there is an inverted U-shaped relationship between urbanization and carbon emissions and the turn point is around 73.80%. But excessive urban concentration can claim the benefits of high-level urbanization. These findings can also help policy makers to use efficient urbanization to curb the carbon emissions, especially for the Asian countries that with high density of population.