Abstract: The effects of enrofloxacin injection （015mg·g-1） on the phaseⅠand phase Ⅱ enzyme activities in liver of Chinese soft\|shelled turtles， Pelodiscus sinensis were investigated in the present study. The sampling interval time were chosen at the initial stages， and 1 h， 2 h， 6 h， 12 h， 24 h， 2 d， 5 d and 10 d after injection， respectively. The results showed that the phaseⅠenzymes APND， ERND and EROD activities were all inhibited by enrofloxacin throughout the trial. The APND activity tended to recover firstly and then decreased significantly， the lowest value was observed in 10 d. ERND activity showed a decline tendency， the inhibition ratio increased significantly at 24 h and then became stable thereafter. The inhibition effect on EROD activity was much stronger at first 12 h. The GSTs activity and MDA content were both induced after enrofloxacin injection， the maximum level occurred at 2 h and 5 d， respectively. In conclusion， the present study indicated that the hepatic phaseⅠandⅡ enzyme of P. sinensis were sensitive parameters to use as biomarkers for evaluating the exposure to aquatic drugs.

Key words: enrofloxacin, Pelodiscus sinensi, hepatic enzyme activities