Abstract: In recent years, the resistance rate and clinical isolation rate of carbapenem-resistant Serratia marcescens have been gradually increasing, which has brought great challenges to the control and clinical treatment of nosocomial infection. S.marcescens can produce drug resistance by carrying the carbapenemase genes, alteration or deletion of outer membrane pore protein, active efflux mechanism, change of target of antibacterial drug and action of integron. The mechanisms of resistance to carbapenems are reviewed based on the literatures abroad and at home, which may provide theoretical basis for clinical antibacterial treatment and development of novel drugs.