Based on 24-h sampling once a week from 9/2003 to 4/2006 in Beijing, 16 PAHs of TSP, the life-time of which is enlarged by the aridity in northern China, were examined by using HPLC. The average concentration of PAHs reached 188.4 ng/m3 and 9.9 ng/m3 for BaP. Both PAHs and BaP increased continuously while the ratio of BaP to PAHs decreased in the past several years. FLT, BbF, BeP and PYR contributed 50.6% to total PAHs, which means 4-ring and 5-ring PAHs were dominant. During three typical heating periods, the concentration of PAHs climbed from 291.0 to 664.9 ng/m3 and 15 PAHs, except COR, went up in different extents; together with PAHs, heavy metal Se and As raised simultaneously. The increase of coal combustion and decease of average temperature in winter, which caused the condensation of PAHs, could explain the above result partly. Also, the temperature increase caused by the improvement of combustion efficiency and technology vapored more PAHs from fuel.