Abstract: Air samples collected from Urumuqi City by grids in winter 2007 were analyzed by GC to understand BTX concentration in air. The results showed that the mass concentrations of benzene, tolzene and xylene were 5.62-20.57, 3.40-122.82 and 2.20-129.15 μg/m³, respectively. Compared to European air standards, benzene mass concentration was high in Urumuqi City, but tolzene and xylene mass concentrations met the European air standard. Tolzene and xylene mass concentrations showed similar spatial distributions, but benzene differed. According to the analysis of population-weighted exposure level (PWEL) of the BTX, the exposure levels of benzene, toluene and xylene were evenly distributed in space; however, the population density was unevenly distributed, so the results showed no correlation. In the center area, the population-weighted exposure concentration of the BTXwas a little lower than that in the whole city area, which indicated that though population density was high in the center, the PWEL of the BTX was lower.