The oysters(Saccostrea cuculiata) were collected from four stations around Xiamen Island(Lundu Port,Xinglin Bay,Tong'an Bay,Huangcuo).The relation between the level of petroleum hydrocarbon in whole tissue and the contents of glutathione(GSH),the activity of selenium-dependent glutathione peroxidase(Se-GPx) and glutathione S-transferase(GST) in digestive gland and gill were investigated.The results showed:(1) The contents of petroleum hydrocarbon in oyster collected from four stations(Lundu Port,Xinglin Bay,Tong'an Bay,Huangcuo) were 380.68,112.34,27.31,20.37μg/g wet weight,respectively;(2) the activity of Se-GPx and GST in digestive gland was lower than that in gill,and the content of GSH seemed reversibly;(3) among the four stations,both Se-GPx and GST activity of digestive gland and gill in Saccostrea cuculiata sampled from the four stations showed a good correlation with whole tissue petroleum hydrocarbon,could be as biomarkers of sea oil pollution.