From October 131, 2006, the research set 3 monitoring points respectively in 4 0meter, 120meter, 220meter platforms and monitored the air quality with PM2.5 concentration. Combined with PM10 concentration and visibility r ange, the temporal and spatial distribution of pollutants was analyzed. The result ind icated that PM2.5 concentration varies obviously at different vertical hei ghts. The overall trend of pollutant distribution at three levels was 120meter >40meter>220meter. The mixinglayer depth and atmospheric stability is the most important factors to influence PM2.5 concentration. PM2.5 conce ntration also varied in different time as follows: from 23:00 to 11:00, the conc entration in 120meter platform was significantly higher than other levels; fro m 11:00 to 18:00, due to the enhancement of atmospheric diffusion capacity, the pollutant concentration at three levels started to decline; from 18:00 to 23:00, the pollutant concentration at lower level showed higher value. Everyday the PM2.5 mass concentration varied in a certain regular way. PM2.5 concen trations peak usually was caused by weather condition and traffic exhauster. And it also indicated that in Tianjin city the overall varying trend of PM10 and PM2.5 concentration seems the same, there was a negative correlation b etween the visibility range and the level of fine particles pollution. The preci pitation process is the important mechanism of removing particle from atmosphere .