Abstract: 126 E. coli isolates of chicken origin were collected from different areas in Shandong province. With the specific primers for the blaCMY-2 gene, 15 isolates were demonstrated to be positive for blaCMY-2 by PCR amplification. Nucleotide sequence analysis demonstrated that the blaCMY-2 sequences of these isolates were identical to that published from GenBank except for strain JN10. Susceptibilities of the 15 isolates to the selected antimicrobial agents were determined by the Kirby-Bauer disk diffusion method, which demonstrated that all the 15 isolates were resistant to cefalothin, cefazolin, cefaclor, cefixime, ampicillin, streptomycin, tetracycline, chloramphenicol and trimethoprim/sulfamethoxazole. Three (JN5, JN9, and HZ9) of the 15 isolates were also resistant to ceftriaxone and ceftazidime. But all isolates were sensitive to cefepime. The modified three dimensional test demonstrated that all the 15 isolates produced CMY-2-type AmpC β-lactamases and four of the 15 isolates produced extendedspectrum βlactamases (ESBLs) at the same time. In addition, the plasmids harbouring the bla_CMY-2 gene were demonstrated to be successfully transferred from E.coli isolates to the recipient E.coli DH5α (sodiumazide resistant mutation) by conjugation experiment. The possibility of the 15 isolates deriving from the same clone was excluded by pulsed-field gel electrophoresis. This study provides a very important theory and research foundation for probing into and resolving the problems of drug-resistance among bacteria. Besides, it also provides important surveillance information for knowing the drug-resistance condition of these E.coli isolates and their dissemination in Shandong province.