Objective To investigate the antimicrobial resistance characteristics of Salmonella spp. isolated from retail whole chickens in Beijing， analyze the prevalence and genomic characteristics of cefotaxime （CTX）-resistant strains.Methods Salmonella strains were isolated from retail whole chickens in urban Beijing， and were subjected to antimicrobial susceptibility testing. CTX-resistant strains were selected for serum-hemagglutination analysis and whole-genome sequencing， and bioinformatics methods were used to analyze the genomic characteristics of the strains.Results The contamination rate was 67.8% （67/87）. A total of 180 Salmonella strains were isolated from 87 samples， of which 98.9% （178/180） of the strains showed resistance to at least one antibiotic， with nalidixic acid （86.1%， 155/180） being the most resistant one， and 69.4% （125/180） of the strains were multi-drug resistant （MDR）. Genomic analysis of 37 CTX-resistant strains identified 6 distinct serotypes and 6 sequence types （ST）， with Kentucky/ST198 （16/37， 43.2%） and Indiana/ST17 （13/37， 35.1%） being the predominant serotype/ST combinations. Core genome multilocus sequence typing （cgMLST） revealed high genetic diversity， which correlated well with serotypes and ST types. The predominant ESBL-encoding gene was bla_CTX-M-55（51.4%， 19/37）. Quinolones resistance was primarily mediated by aac（6'）-Ⅰb-cr （29.7%， 11/37） and chromosomal point mutations， among them 75.7% of the strains notably harbored four mutations simultaneously at sites in GyrA （S83F， D87N/D87G） and ParC （T57S， S80I/S80R）. Additionally， three imipenem- resistant Salmonella Indiana strains harbored the bla_NDM-5 gene.Conclusion Salmonella contamination in retail whole chickens in urban Beijing is highly widespread， accompanied by a high prevalence of antimicrobial resistance. Most CTX-resistant strains harbored multiple resistant mechanisms. Notably， the detection of carbapenem resistance in MDR Salmonella Indiana poses new risks and challenges for public health and clinical infection treatment.