Air pollution has become a severe threat and challenge in China. Focusing on air quality in a heavily polluted city (Weifang Cty), this study aims to investigate spatial and temporal distribution characteristics of air pollution and identify the influence of weather factors on primary pollutants in Weifang over a long period from 2014-2018. The results indicate the annual Air quality Index (AQI) in Weifang has decreased since 2014 but is still far from the standard for excellent air quality. The primary pollutants are O (Ozone), PM (Particles with aerodynamic diameter ≤10 µm), and PM (Particles with aerodynamic diameter ≤10 µm); the annual concentrations of PM and PM show a significant reduction but that of O is basically unchanged. Seasonally, PM and PM show a U-shaped pattern, while O exhibits inverted U-shaped variations, and different pollutants also present different characteristics daily. Spatially, O exhibits a high level in the central region and a low level in the rural areas, while PM and PM are high in the northwest and low in the southeast. Additionally, the concentration of pollutants is greatly affected by meteorological factors, with PM being negatively correlated with temperature and wind speed, while O is positively correlated with the temperature. This research investigated the spatiotemporal characteristics of the air pollution and provided important policy advice based on the findings, which can be used to mitigate air pollution.