Abstract: To investigate the resistance to aminoglycosides in Enterobacteriaceae isolated from two pig farms， Enterobacteriaceae isolated from two pig farms were screened for the presence of the rmtA, rmtB, armA，rmtC genes and 10 aminoglycosides modifying enzyme genes by PCR and sequencing. Conjugation experiments were carried out to study the horizontal transfer mechanism of rmtB and 10 AME genes. All isolates and their transconjugants were tested for susceptibility to 20 antimicrobial agents by the broth microdilution method. Of 152 Enterobacteriaceae isolates recovered from two pigs, 49 strains(323%) were positive for the rmtB gene, including 48 strains of Escherichia coli and a single isolate of Enterobacter cloacae. No other kind of the 16S rRNA methylase genes was detected. 7 AMES genes including aac(3)Ⅱ，aph(3′)Ⅶ，aph(3′)Ⅱ，aadA1，aac(6′)Ib，aac(3)Ⅳ and aph(4)Ⅰ were presented in 49 rmtBpositive isolates. The present rate of the 7 AMES genes were ordered as 935%（aac(3)Ⅱ）,796%（aph(3′)Ⅱ）,776%（aph(3′)Ⅶ）,345%（aadA1）,143%（aac(6′)Ib）,102%（aac(3)Ⅳ） and 82%（aph(4)  I）. Total of 46 rmtBpositive isolates transferred their rmtB, aac(3)Ⅱ，aph(3′)Ⅶ，aph(3′)Ⅱ and aadA1 easily to recipients of E.coli C600 and E.coli 488 Rifr. Conjugative transfer frequencies varied from 30×10-6 to 46×10-13 transconjugants per recipient. All 49 rmtBpositive isolates and 46 transconjugants showed extraordinarily highlevel resistance to 4,6substituted deoxystreptamine (MICs, >512 μg·mL-1) and other aminoglycosides .The results indicated that 16S rRNA methylases RmtB and 10 AMEs were widely spread in veterinary clinical isolates from two pig farms.They mediated the highlevel resistance to 4,6substituted deoxystreptamine and other aminoglycosides.They located on the conjugated plasmid and transfer resistance of aminoglycosides together.