Benzo[a]pyrene (BaP) is one of the most important pollutants in the marine environment. The effects of benzo[a]pyrene on detoxifying enzyme activities (EROD, GST), antioxidant enzyme activities and (SOD) and lipid peroxidation levels (LPO) with a BaP exposure period (fifteen days) and elimination period (fifteen days) in gill and liver of Portunus trituberculatus were studied. The results showed that the activities of four toxicology parameters were significantly induced by BaP in the first day (P<0.05) and exhibited a direct correlation with the concentration of BaP. From an overall perspective, the activities of EROD, GST in the liver and the activities of SOD in gill declined after the peaks, while the activities of SOD in liver and content of MDA in liver and gill continued to rise. The time of the activities of EROD, GST and SOD reached their max value in gill was shorter than in the liver, the activities of EROD, GST, SOD and content of MDA in gill was lower than in liver, too. During the elimination period, the activities of SOD in gill with high exposure concentrations (0.45 μg/L) and in liver with both exposure concentration could not resumed to the command level (P<0.05), in contrast, the other groups could resumed to the command level (P>0.05). The results of this experiment indicated that both gill and liver of P. trituberculatus possessed resume capacity, gill was more sensitive to BaP than liver.