Abstract: OBJECTIVE To understand the molecular epidemiological characteristics of mcr-1 gene-positive Escherichia coli and the status of carrying drug-resistant genes and virulence genes in hospitalized patients, and to provide a basis for clinical diagnosis and treatment of the disease and prevention and control of nosocomial infections. METHODS Total of 1 018 strains of E. coli isolated from various clinical specimens from Nov. 2008 to Dec. 2018 were retrospective analyzed. Polymyxin resistance gene mcr-1 was detected by PCR assay and micro broth dilution method and agar dilution method was used to detect the minimum inhibitory concentration（MIC） of mcr-1 positive strains to polymyxin and other antibiotics. Phylogenetic group classification of mcr-1 positive strains was performed by multiplex PCR, and Construct a phylogenetic tree was constructed by whole genome sequences. Multilocus sequence typing（MLST）, virulence gene and drug resistance gene were analyzed. RESULTS Among 1 018 strains of E. coli,11 strains were positive for mcr-1 gene with the detection rate was 1.08%; The mcr-1 gene-positive E. coli phylogenetic groups belonged to groups A,B1 and D,respectively. The phylogenetic tree showed that mcr-1 positive strains belonged to seven different clades, and MLST showed that mcr-1 positive strains belonged to 6 different ST types. The mcr-1 gene-positive E. coli exhibited multi-drug resistance and produced extended-spectrum β-lactamase. It also contained many virulence genes such as coding protective factor（iss, traT,etc）,adhesion（lpfA,papA/papC and yfcV）,iroN uptake system（sitA,chuA,fyuA,irp2,iucC,iutA and iroN）,toxin, invasion and so on. CONCLUSION The prevalence of mcr-1 gene in E. coli in the hospitals is low, which mediats low levels of polymyxin resistance; mcr-1 positive E. coli carries multiple virulence genes and exhibits multi-drug resistance, and there is cross infection in the hospital.