Imported air pollution has a significant impact on urban air quality. Many urban air pollution events are not caused by local emissions, but by the transport of air pollutants from surrounding areas. Therefore, it is very necessary to prevent and control imported air pollution. However, the existing supervision of urban air quality mostly relies on ground monitoring stations, which is extremely limited in time and space. In this paper, MERRA-2 data is used to grasp urban air quality from a more macroscopic perspective, and combined with ground monitoring station data and meteorological data, the transmission route of air pollution is reconstructed. This paper takes Xuzhou City, Jiangsu Province as an example. It is proved that this method is highly feasible and can provide scientific data support for efficient prevention and control of imported air pollution.