Levels, spatial and temporal trends of 16 polycyclic aromatic hydrocarbons (PAHs) in oyster Crassostrea rivularis along the Hainan Island coast were investigated from 2009 to 2014. Results showed that the total concentrations of PAHs in oysters ranged from 289 to 2426ng/g with an average of 856.7ng/g on a dry weight basis. The PAHs levels from Hainan Island coast fell within moderate levels compared with those from other coastal areas in the world. The average concentrations of PAHs exhibited definite spatial differences and decreased in the order : Basuo Harbor> Yulin Harbor> Maniao Harbor>Dongzhai Harbor. Based on Mann–Kendall test, only Basuo Harbor showed a significant increasing trend (P<0.05). The composition of PAHs was characterized by 2~3rings of PAHs (ranging from 62.3%~92.5%). PAHs may originate mainly from petroleum and combustion of oil. Risk assessment suggested that the cancer risks in oysters from Basuo Habor exceeded the maximum acceptable risk (10-5), but did not reach the serious cancer risk level (10-4), while the cancer risks in other sites were acceptable. Further assessment suggested that daily intake of edible oyster tissue from Basuo Habor and other areas of Hainan Island should not exceed 56g and 67g, respectively.