Air pollution is a major challenge for the improvement of urban environmental quality. The process of urbanization is an important cause of highly complex air pollution, on the other hand it also provides artificial reinforcement conditions for self-purification of air pollutants in cities. "Environmental catalytic city" refers to the spontaneous catalytic purification of low concentration gaseous pollutants in the atmosphere by catalytic materials coating on the artificial surfaces, such as building surfaces in the city under natural photothermal conditions. "Environmental catalytic city" is of great significance for the control of complex air pollution without additional energy consumption, the continuous improvement of indoor and outdoor air quality, and the scheme and construction of " self-purifying city". Here, we propose the concept of “environmental catalytic city”, and discuss its further improvement, development, and application.