[Objective] Studying the relationships among issues of urbanization, economic growth and nitrogen emission in 31 provinces of China from 2001 to 2015, and to provide theoretical support for the sustainable development of urban environment.[Methods] Co-integration test, panel unit root test, and Granger statistical causality test were used jointly.[Results] (1) The urbanization of China, particularly of the western, central and eastern areas, contributed to the economy development. The urbanization and the successive economy development led to the increase of nitrogen emission. The urbanization in western area contributed more proportional than it did in central and eastern areas. In contrary, the economy development in eastern areas had lager contribution. (2) The panel causality results revealed that there were a long-run bidirectional causal relationship among urbanization, economy development and nitrogen emission. Two unidirectional links were found, one was from urbanization to economy development, another one was from urbanization and economy development to nitrogen emission. For different region, the causal relationship exhibited different direction traits. In eastern and central areas, the relationship between urbanization and economy development was long-run bidirectional. While the link from urbanization to N emission, and the link from economy development to N emission were both short-run and unidirectional.[Conclusion] The government should reduce the amount of nitrogen by controlling the speed of economic growth and urbanization, and by adjusting the industrial structure and increasing the utilization rate of energy.