The organic pollutants and their concentrations in air collected in eight site in Lanzhou were analyzed by SFE-GC/MS. The optimum SFE condition is 22MPa, 80°C. The highest total pollutants concentrtion was found in the Lanzhou oil refining factory (285. 75μg · m-3), and the lowest total pollutants concentration was found on the crest of Lan hill (59. 55μg · m-3). We have also studied the relationship between the pollu-tants concentration and sampling time and weather. The pollution in fine day was high-est ...