Abstract: In order to determine the serotypes of enteropathogenic E.coli strains and the susceptibility to Antibiotics in Hebei, Beijing and Tianjin, 55 pathogeic E.coli stains were isolated from 60 E.coli strains in 10 pig farms, and their susceptibility to antibiltics were analysed and supervised. The result shows that the predominant serotypes were 60%(33/55), they were O101, O152, O93, O78 and O54. They efficient antibiotics were Ceftriaxone sodium, Polymyxin, Cefobid, Cephalothin and Spectinomycin to the 60 E.coli stains, and the sensitive ratio were 95.0%(57/60), 90%(56/60), 88.3%(53/60), 86.7%(52/60) and 85%(51/60) respectively. And the antibiotics susceptibility testes show all strains had the tolerance to the used drugs of different levels. It was 80%, 53.3%, 75%, 86.7%, 76.7%, 71.2%, 51.7%, 75%, 70% and 55% that tolerance to Streptomycin, Gentamicin, Ampicillin, Sulfamethoxacin-Trimethoprimum, Mequindocis, Furazolidone, Norfloxacn, Ciprofloxacin, Olaguindox, Lomexasin and Folrfenicol respectively. And 80% strains had tolerance to more than 6 kinds of drugs, 17%, 15% and 12% strains separately tolerant to 8, 10 and 6 kinds of drugs.