The depletion rules of enrofloxacin and its metabolite residues were studied in channel catfish (Ietalurus punetaus) feeding with 20 mg/kg and 40 mg/kg enrofloxacin for 5 d under pond conditions. The results showed that the peaking time (tmax) of enrofloxacin in the liver was 3 d at low dose, and 4 d at high dose during the period of treatment, and the corresponding maximal drug concentration (Cmax) was 12.24 mg/kg and 15.97 mg/kg, respectively. The equations of elimination curve of enrofloxacin in the liver, muscle and blood were C=0.25e-0.136t, C=0.31e-0.082t and C=0.23e-1.37t, and the elimination halflives were 5.10 d, 8.43 d and 5.06 d at dose of 30 mg/kg, respectively. The equations of elimination curve of the drug were C=0.70e-0.173t, C=0.50e-0.096t and C=1.08e-0.182t, and the elimination halflives were 4.00 d, 7.22 d and 3.81 d at dose of 60 mg/kg, respectively. Enrofloxacin was changed into ciprofloxacin in channel catfish. The concentration of enrofloxacin in the muscle was 0.013 mg/kg after 138 d at low dose, and 0.019 mg/kg after 138 d at high dose. The elimination rate of the drug in various tissues was in the order of blood, liver and muscle.