In this study we explored the elimination rules of semicarbazide (SEM) and its effect on the activities of hepatopancreas enzymes in Fenneropenaeus chinensis. Experimental shrimps were fed with a diet supplemented with nitrofurazone for five days before they were randomly selected from the tank and sampled in different days after the last oral administration. The concentrations of SEM in the hemolymph，hepatopancreas, gill, muscle and carapace were measured with LC-MS/MS, and the activities of ethoxylcumarin odethylase (ECOD) and aminopyrine N-demethylase (APND) in the hepatopancreas were examined with UV spectrophotometry and fluorospectrophotometry. The results showed that 1 h post treatment, the mean concentrations of SEM in the shrimp tissues were in the order of hepatopancreas>gill>carapace>muscle>plasma. At the end of the 20th day post treatment, SEM was still detectable in all tissues and the order of the concentration was muscle>gill>carapace>plasma> hepatopancreas. The half life of the elimination phase in the muscle, carapace, gill, plasma and hepatopancreas was 5.89 d, 4.66 d, 2.95 d, 2.70 d and 1.47 d respectively. Our results indicated that the elimination of SEM was the fastest in the hepatopancreas and the slowest in the muscle, and that SEM remained in the body of F. chinensis for long. Compared to the control, the activities of ECOD and APND in the experimental group were first reduced, followed by an increase, and finally returned to the normal levels. The activity of ECOD in the experimental group was significantly lower than the control 1 h post treatment (P<0.05), and the statistical significance was even greater than 3 h post treatment (P<0.01). Afterward the activity was enhanced and became significantly higher than the control at 48 h, 72 h, 96 h, 120 h, and 240 h (P<0.01) post treatment. The activity of APND was significantly lower than the control at 6 h and 9 h (P<0.01) but obviously higher at 96 h (P<0.05) and 240 h (P<0.01), and the final level was lower than the control at 480 h. These data suggested that SEM was eliminated slowly in F. chinensis and had an impact on the activities of ECOD and APND. Moreover, ECOD and APND may be involved in the metabolism of nitrofurazone.