Abstract: In this study, the malondialdehyde (MDA) content, the glutathione peroxidase (GPx) activity, and the superoxide dismutase (SOD) activity in black porgy Sparus macrocephalus were determined after the acute exposure to TBTCl at the concentration of 4 and 20 μg · L^-1. Results showed that TBTCl inhibited the SOD activity in S.macrocephalus gill slightly, but there was an obvious promotion on the SOD activity in S.macrocephalus liver. After 24 h exposure to TBTCl, the MDA contents in two tissues increased significantly (P < 0.05) with the increase of the concentration of TBTCl compared with the control. However, the MDA contents decreased and were lower than the control after 48 h exposure. The effects of TBTCl on the GPx activity in S.macrocephalus had obvious difference between gill and liver; the GPx activity in gill was significantly inhibited after 24 h exposure, and then was promoted significantly with the increase of exposure time. There was a significant promotion in S.macrocephalus liver and reached the peak at the concentration of 20 μg · L^-1 TBTCl. The significant changes subjected to oxidative stress and damage exposed to TBTCl indicated that they could be used as the sensitive biomarker to monitor the pollution level of organic compounds.