Based on analyzing the data of some elements (including lead) and lead abundance ratio in air dust near the ground surface in Chengdu City, this paper has reached the conclusion that lead pollution is heavy. The spatial distribution of aerosol lead varies remarkably in the range from 119.76×10^-6 to 1327.42×10^-6 with an average of 374.51×10^-6, SD of 273.36 and CV of 0.730. The radiogenic lead of coal fly ash is obviously higher than that of gasoline and diesel oil, which can serve as the discrimination criterion to distinguish the aerosol lead sources. The data of lead isotopic compositions of aerosol lead show that the pollution is caused by multiple pollution sources, with the relatively clean area mainly by construction and soil dust, the moderately polluted area chiefly by automotive emissions and dust, and the heavily polluted area predominantly by coal fly ash, automotive emissions and industrial pollutions.