Abstract: Twelve size segregated particulate samples in inhalable particles from urban-rural transition site and suburban site in Beijing in the winter are collected. Seventy-five polycyclic aromatic hydrocarbons (PAHs) are identified. U.S. EPA 16 priority PAHs are quantitatively analyzed by GC-MS and its size distribution characteristics also discussed. The result shows that the concentration of PAHs in inhalable particles at urban-rural transition sites is higher than that at suburban sites. About 68% and 85% of priority PAHs are adsorbed on particles smaller than 2.0 μm at suburban site and urban-rural transition site respectively. PAHs with more than four rings are enriched in inhalable particles at the two sites. The major pollution source is possibly combustion of fossil fuel and influence from coal combustion is predominant.