Abstract: The airborne particle samples were collected onto the glass filter with a five stage cascade impacter sampler. The samples gathered from rural and urban area of Beijing in four seasons in 2003 were analyzed. The aromatic fractions were analyzed by gas chromatography-mass spectrometry. The characteristic of the contents of total priority polycyclic aromatic hydrocarbons (PAHs) of different seasons shows that winter is the most,autumn is the second, spring is the third and summer. Particle size distribution of PAHs with different rings were compared. The result shows that the ratios of 2 or 3rings PAHs in the grain particles are bigger than those of high rings PAHs.