Objective To study the distribution of lipophilic corynebacterium in the breast puncture fluid of the patients with non-lactating granulomatous mastitis and its sensitivity to antibacterial drugs.Methods Twenty patients with non-lactating granulomatous mastitis treated in this hospital from September 2017 to May 2018 were selected as the study subjects.The pus samples after 48 h culture negative were collected and conduced the fastidious bacterial culture by extending the culture time and changing the culture condition.The 16S rRNA sequencing analysis and matrix assisted laser desorption ion flight mass spectrometry were used to bacterial identification.The E-test method was used to determine the minimum inhibitory concentration(MIC)and the EUCAST standard was used for conducting the sensitivity interpretation.The control lipophilic experiment was performed by adopting the 1%tween 80 blood plate.Results There were 20 strains of isolated fastidious bacteria,including 16 strains of Corynebacterium kroppenstedtii,1 strain of Corynebacterium tuberculostearicum,1 strain of Corynebacterium sp and 2 strains of anaerobic bacteria(Peptoniphilus harei and Propionibacterium avidum).One strain of bacillus stearate was highly sensitive to all tested drugs,and other 17 strains of corynebacterium were sensitive to penicillin and most cephalosporins,but highly resistant to erythromycin and clindamycin,and a few strains showed high resistance to levofloxacin.The lipophilic experiments showed that all corynebacterium showed good lipophicity.Conclusion Lipophilic corynebacterium,especially Corynebacterium kroppenstedtii is closely related to non-lactation granulomatous mastitis.Lipophicity is an important pathogenic factor.The laboratory must pay great attention to improve the culture conditions and use matrix assisted laser desorption ion flight mass spectrometry for conducting the accurate identification in order to improve the detection rate of culture.Clinical treatment is recommended to use linezolid antibacterial drugs with good lipophilicity and sensitivity for conducting the goal-oriented treatment.