In order to clarify the difference in the pharmacokinetic parameters of difloxacin in diseased and healthy Carassius aurutus gibelio and to provide the scientific data for the rational use of difloxacin, C.a.gibelio was infected in wound with the optimal concentration of Aeromonas hydrophila. The pharmacokinetic parameters of difloxacin in the diseased C.a.gibelio were tested through an established reversed-phase high performance liquid chromatography method, and data were compared to those obtained from the healthy control C.a.gibelio. The results showed that the concentration-time curves of difloxacin orally administered at a dose of 20 mg/kg body weight in the diseased and healthy C.a.gibelio were both in accordance with the first order absorption and open two-compartment models. The pharmacokinetic equations were C=6.227e^-0.109t-8.074e^-2.752t+1.847e^-0.006t and C=110.295e^-0.331t+1.533e^-0.01t-111.828e^-0.412t, respectively. However, compared to the pharmacokinetic parameters of difloxacin in the healthy C.a.gibelio, the difloxacin's absorption, distribution and elimination speeds in the diseased C.a.gibelio were reduced. The distribution half-life, elimination half-life, absorption rate constant, area under a curve of difloxacin in the diseased C.a.gibelio were increased by 4.25 h, 36.17 h, 2.34/h and 74.52 mg·h/L, respectively, and its time on the break point was extended 5.75 h, its peak of plasma concentration was decreased by 61.16% and its reabsorption disappeared. The present study confirmed that the liver and kidney functions of C.a.gibelio could be damaged by A.hydrophila infection, and the absorption, distribution and elimination of difloxacin in the diseased C.a.gibelio could be slowed.