Objective To better understand the epidemiology of this MDR clone and its potential for international spreading， the epidemiological characteristics and antibiotic resistance of Salmonella enterica serovar typhimurium （S. typhimurium） and monophasic variant 1，4，［5］，12∶i∶- （S.1，4，［5］，12∶i∶-） in Guangxi Zhuang Autonomous Region in 2021 were investigated.Methods Two hundred and seventy six strains of Salmonella from clinic samples were serotyped according to the Kauffmann White scheme by slide agglutination. A strain was confirmed as monophasic by multiplex PCR when phase-2 flagellar antigen was negtive after three times phase inversion. The strains were tested for antimicrobial susceptibility by disk diffusion method.Results Two hundred and one （72.8%） isolates of monophasic S. typhimurium and 75 isolates of S. typhimurium were identified by a specific multiplex polymerase chain reaction. Resistances to trimethoprim/sulfamethoxazole and chloramphenicol in S. typhimurium were higher than monophasic S. typhimurium significantly （P<0.05）. Resistances to ampicillin， cefotaxime， nalidixic acid， gentamicin and tetracycline in monophasic S. typhimurium were higher than S. typhimurium significantly （P<0.05）. Two serotypes of S. typhimurium were found to be resistant to over 79% of three classes or more antimicrobial agents. The common multiple dominant drug resistance spectrum was ampicillin， chloramphenicol， trimethoprim/sulfamethoxazole and tetracycline pattern.Conclusion Monophasic Salmonella typhimurium had replaced S. typhimurium as predominant serotype in diarrhea patients in Guangxi. The drug resistance of two serotypes Salmonella was not optimistic， especially the rapid increaseof multi-drug resistance isolates. Targeted efforts is needed to enhance foodborne S. typhimurium and monophasic S. typhimurium surveillance， which can reveal the underlying determinants of resistance in different microorganisms， and measure the effectiveness of interventions.