Pharmacokinetics of two different forms of marbofloxacin was investigated following intramuscular and oral administration methods to evaluate the safety for clinical use.Six healthy native dogs at a single dosage of 2.75 mg per kg body weight were chosen by this crossover design trial.Marbofloxacin concentration in plasma was determined by a high performance liquid chromatography with inner standard method.The parameters were concluded by 3P97 computer program.The concentration-time data were both fitted a one-compartment open model after intramuscular and oral administration of marbofloxacin.The main pharmacokinetic parameters were as follows:T1/2ka(0.52±0.41) h and (0.41±0.13) h，T1/2ke(4.40±1.86) h and (6.25±1.80) h，Tpeak (1.53±0.75) h and (1.68±0.39) h，Cmax(1.36±0.38) μg/mL and (0.93±0.06) μg/mL，AUC (10.64±2.66)（μg·h）/mL and (8.68±1.98)（μg·h）/mL,respectively for intramuscular and oral administration.The results showed that the pharmacokinetic characteristics of marbofloxacin in healthy dogs manifested the rapid absorption,big apparent volume of distribution,slow elimination.And oral adminstration showed more wide and deep tissue distribution than intramuscular adminstation.