Abstract: With to the synoptic data and Pollution density observed at some main city spots of Pearl River Delta between 1986-1993, the frequency of synoptic patterns in which Pollution density exceeds standard II in different months have been calculated. The relationship between synoptic pat terns and density of surface air Pollution over Pearl River Delta is qualitatively determined. It reveals that the density of air Pollution particles (SO₂, NO_x, TSP, CO etc. ) changing not only closely with the synoptic pattern on observational days, but also with the duration of synoptic patterns I the surface and upper air situation, the motion of front and motion of tropical cyclone ohserved a few days before the observation.