Abstract: OBJECTIVE To identify one strain of Corynebacterium tuberculostearicum isolated from the abdominal drainage fluid of an ectopic pregnancy patient after surgery and analyze the drug resistance so as to provide guidance for clinical identification and use of antibiotics. METHODS The preliminary bacterial identification was carried out by means of morphology, catalase test, and the species was finally determined through the matrix assisted laser desorption Ionization time of flight mass spectrometry (MALDI-TOF MS). The minimum inhibitory concentrations (MICs) of antibiotics and inhibition zone diameters were detected with the use of disk diffusion method. RESULTS One strain of gram-positive Corynebacterium was isolated, and the MALDI-TOF MS showed that it was C. tuberculostearicum. The drug susceptibility testing indicated that the strain was in vitro susceptible to vancomycin, linezolid, imipenem, amoxicillin, amoxicillin-clavulanic acid, ceftriaxone, cefepime, and ceftazidime and that it was resistant to the rest of antibiotics. CONCLUSION It is very difficult to identify the C. tuberculostearicum in common laboratory and is necessary to conduct the MALDI-TOF MS or 16S rRNA gene sequencing. The strain shows multidrug-resistant. The in vitro sensitive antibiotics may be ineffective for the clinical treatment; vancomycin and linezolid are preferred for the treatment.