Abstract: ObjectiveThe present study determined antimicrobial resistance of pathogenic Escherichia coli isolated from pig in Guangxi in 2007 and 2016,so as to provide a foundation for the use of antimicrobials in veterinary clinical med-ication for prevention and treatment of porcine colibacillosis. MethodTwo hundred samples of intestinal content, rectum cotton swab, or mesentery lymph node of diarrhea piglets were collected from twenty-five pig farms in Guangxi to isolate E. coli, pathogenicity of the isolates was detected. One hundred and three pathogenic strains were selected for in vitro an-timicrobial sensitivity test. The results were compared with those in 2007. ResultOne hundred and seventy-eight E. coli strains were isolated from the samples with isolation rate of 89%, one hundred and forty-three strains of them were deadly to lab mice. In terms of drug susceptibility of pathogenic E. coli from pig, its drug susceptibility toward 50% of antimi-crobials(nine kinds) increased while the other 50%decreased in 2016 compared to 2007. The increase of drug susceptibi-lity of spectinomycin was the maximum ( 34 . 9%) while the decrease of drug susceptibility of florfenicol was the maxi-mum(46.9%). Intermediary rate of ceftriaxone and doxycycline remained stable, but intermediary rate of other 16 antimi-crobials decreased in 2006 compared to 2007. The most obvious one is cephradine, which reduced by 55.2%. The statistical results of resistance rate showed that only three kinds of antimicrobial ( amikacin , spectinomycin and doxycycline ) de-creased by 12.3%-15.5%,while the other fifteen kinds of antimicrobial increased by 1.2%-62.1%,and resistance rate of amoxicillin increased by 62.1%, resistance rate of florfenicol increased 57.0%. The results showed that, 75.7% of the strains isolated in 2007 were resistant to 5-11 kinds of antimicrobial agents, while 74.8% of the strains isolated in 2016 were resistant to 11 kinds of antimicrobial agents. ConclusionAt present, pathogenic E. coli isolated from pig in Guangxi are mainly broad spectrum resistant, drug susceptibility and intermediary rate decrease and drug resistance rate increases greatly. Amikacin and spectinomycin can be used in production for prevention and treatment of porcine colibacillosis.