Abstract: Due to the outbreak of a deadly disease on Chinese turtle (Trionyx sinensis), this study aims to find out the pathogenic factor, and identify the biological status, the etiology and drug resistance characteristics of isolated bacteria. Three pathogenic bacteria assigned as C1, C2, C3 were isolated from the diseased Chinese turtle (Trionyx sinensis). The pathogenic effect of the isolated bacteria was determined through artificial regression on healthy Chinese turtle. Species of bacteria were classified through morphological observation, physiological and biochemical identification, 16S rRNA sequencing and phylogenetic analysis. Kirby-Bauer agar diffusion method was used for the drug sensitivity test. The three isolated bacteria strains were classified as Citrobacter freundii, Morganella morganii, and Klebsiella pneumoniae. Isolated bacteria could cause acute infectious disease on healthy Chinese turtle, and the mix of 3 species of bacteria could lead to almost 100% mortality. Drug- sensitivity tests showed that Citrobacter freundii were highly sensitive to Ceftazidime, Ceftriaxone and Levofloxacin, while extremely resistant to 17 kinds of drugs such as Vancomycin; Morganella morganii were very sensitive to Ceftriaxone, Ceftriaxone and highly resistant to 17 kinds of drugs such as Clindamycin; Klebsiella pneumoniae were hypersensitive to 13 kinds of drugs such as Enrofloxacin and extremely resistant to 6 kinds of drugs such as Penicillin. This study showed that Citrobacter freundii, Morganella morganii and Klebsiella pneumoniae were the pathogenic bacteria which caused the deadly disease outbreak on the Chinese turtle. The pathogenicity of the 3 mixed isolate bacteria was stronger than any single bacteria strain. Citrobacter freundii and Morganella morganii showed a high degree of multi-drug resistance, while resistant tendency of Klebsiella pneumoniae is different from the others, which was a weak resistant strain.