In this study, the pharmacodynamics (PK) of thiamphenicol on pathogenic Aeromonas hydrophila strain (AH10) and the pharmacokinetic (PD) parameters of thiamphenicol in crucian carp(Carassius auratus)were investigated by high-performance liquid chromatography (HPLC) system, which were used to draw reasonable medication regimen to control disease and prevent drug resistant bacteria. The in vitro pharmacodynamic results showed that the minimal inhibitory concentrations(MIC) of thiamphenicol on AH10 was 1.0 μg/mL, and the minimal bactericidal concentrations (MBC) was 2.0 μg/mL; the mutant prevention concentration (MPC) was 8.0 μg/mL (8MIC); the mutant selection window (MSW) of thiamphenicol on the pathogenic bacterial strains was 1.0-8.0 μg/mL. The time of thiamphenicol concentration in serum of crucian carp above MPC was 3h at the dosage of 20 mg/kg; 8h at the dosage of 30 mg/kg, 22 h at the dosage of 40 mg/kg, respectively;AUC₂₄(Area under the drug concentration-time curve)/MIC and C_max(Maximum concentration in the interval)/MIC of thiamphenicol in serum were 89.539 and 14.92 at the dosage of 20 mg/kg, respectively; 174.560 and 17.69 at the dosage of 30 mg/kg, respectively; 251.682 and 24.22 at the dosage of 40 mg/kg, respectively. Considering the drug remained in the plasma with a concentration above MPC for 24 h and AUC₂₄/MIC>125 or C_max/MIC>10, it is suggested that hemorrhagic septicemia can be controlled using a dosing regimen of 40 mg/kg thiamphenicol, at intervals of 24 h. The proposed withdrawal time in crucian carp should not be less than 15 d at the water temperature of (22±1)℃.