Based on the monitoring data of everyday air quality of Weifang Environmental Monitoring Center and the observations of Weifang Meteorological Bureau from 1993 to 2002,the temporal-spatial characteristics,the variation tendency of the urban air quality and their relations with the meteorological conditions are analyzed. Results indicate that the TSP is concluded as the primary pollutant in those three matters (SO₂,NO_Xand TSP,which affect the urban air quality of Weifang),those three matters are more in the winter half year and less in the summer half year,and their densities have decreased with years. According to the grading of National Unified Standard,the air quality grades of 33.5% of the days are above the third grade (API>100) ,which decrease 5.96 days per annum. In accordance with the urban air quality,the relationships between the height of the mixed layer,fog and the other weather phenomenon (soot,floating dust and flying sand) and the air pollution are analyzed.