Abstract: The pharmacokinetic properties of ofloxacin (OFL) sustain-released injection in swine were studied by 10 mg/kg dosage administration of OFL. The concentrations of OFL in the plasma were determined by reversed-phase HPLC-FLD. Pharmacokinetic analysis was carried out by using a computer program (3p97, China Pharmacology Association). The OFL concentrations-time data were best described by a one-compartment open model after single intravenous administration of the OFL injection. The OFL concentrations-time data were both described by a one-compartment open model with first order absorption after single intramuscular administration of the OFL sustain-released injection and the OFL injection. The t_1/2ka,t_1/2ke,T_max, C_max and the bioavailability after intramuscular administration of the OFL sustain-released injection were（0.292 0±0.102 4）h, （6.902 2±0.901 9）h, （1.379 5±0.373 2）h,（2.148 1±0.296 1） μg/mL and （95.70±12.56）％，respectively. Moreover, its effective time （MIC=0.5 μg/mL）could be maintained （15.736 4±1.854 2） h. Compared with the OFL injection, t_1/2ka and t1_/2ke of the OFL sustain-released injection were both extended, and its T_max was delayed. Its C_max was reduced, and it had better bioavailability. These experimental results indicated that the OFL sustain-released injection has sustained-released and long-acting properties.