In order to investigate the MDR gene by plasmid profile, multiplex-PCR and PFGE analysis, it was examined 20 Salmonella Typhimurium isolated from patients stool from 1999 to 2002. The plasmid profile analysis was shown one to five kinds of plasmid in 600bp~150Kb sized. Especially, PT104 isolates obtained has 3 plasmid identically. According to the result of multiplex-PCR, all PT104 isolates amplified only tet(G) and pse1, but aadA2 was not specialized. PFGE analysis of the fragments restricted by XbaⅠ evidently discriminated plasmid DNA among phage types.