Objective To provide rational use of vancomycin in elderly MRSA-infected patients, compared its pharmacokinetics in the elderly MRSA-infected patients with healthy young subjects.Methods 15 elderly MRSA-infected patients and 15 healthy young subjects were injected with 1.0g vancomycin.Serum concentrations were determined by fluorescence polarization immunoassay(FPIA) in both groups(n infected=15,n healthy =15),then calculated the pharmacokinetic parameters with program 3p97.Results Compared with the healthy group, the elimination half life (t1/2β)were longer, the apparent volume of distribution (Vd)and the area under curve(AUC)were increased,the creatinine clearance(Ccr)were lower in the infected group.The differences of these pharmacokinetic parameters between the two groups were statistically significant(p<0.01) except the peak serum concentrations(p>0.05).Conclusion Vancomycin should be used with decreased dose or increased interval in the elderly MRSA-infected patients, therapeutic drug monitoring and personalized medicine were required.