The concentrations of polycyclic aromatic hydrocarbons (PAHs) in the atmospheric particles in major city of Yangtze River Delta were investigated.PM2.5 samples were collected in Shanghai, Nanjing and Ningbo city during Nov 2014, Jan 2015 and Apr 2015.These samples were analyzed by gas chromatography-mass spectrometry (GC-MS) for characterizing the compositions and seasonal variation of particulate PAHs.The results showed that the concentrations of total PAHs in shanghai, Nanjing and Ningbo were 15.7 ± 9.10 ng· m-3, 21.7± 8.70 ng· m-3 and 33.0±17.8 ng·m-3 in Autumn, respectively;21.0 ±20.3 ng·m-3, 29.4±14.0 ng·m-3 and 38.3±32.4 ng·m-3 in winter;12.8±7.90 ng·m-3, 12.1±6.10 ng·m-3 and 14.6± 8.40 ng.m-3 in spring.Pollution levels of particulate PAHs were listed in the following order: winter > spring > autumn.And the concentrations of particulate PAHs in Ningbo were higher than other two cities in all seasons.According to diagnostic ratios and principle components analysis (PCA)methods, combustion, coal burning and vehicle emissions were the dominant sources of PAHs in Yangtze River Delta.Their toxic equivalence factor (TEF) and carcinogenic risk assessment indicated that pollution of PM2.5-bound PAHs in this case was still under a low level.However, this study implied that some regulations on various anthropogenic sources should be taken in account, in order to decrease human health risk of atmospheric PAHs.