The quinolone-resistant isolates were screened from 945 foodborne Listeria monocytogenes, aimed to explore the potential molecular mechanisms of quinolone resistance in Listeria monocytogenes. A total of 32 isolates exhibited quinolone resistance by the KB method. Gene mutation in quinolone resistance-determining region(QRDR) and the distribution of plasmid-mediated quinolone resistance (PMQR)genes were detected by PCR. The MIC values of ciprofloxacin with or without efflux pump inhibitor reserpine were measured. Compared to QRDR of these genes in quinolone-sensitive Listeria monocytogenes EGDe, no amino acid substitution was observed in 32 quinolone-resistant isolates, and no PMQR gene was also found in all these strains. However, seven kinds of amino acids substitutions of fepR were found, whether these mutations were critical to the quinolone resistance still to be elucidated. The presence of efflux pump lde gene was 100% in all 32 strains of Listeria monocytogenes by PCR. However, after the efflux pump inhibitor reserpine addition, the MIC value of ciprofloxacin in 25 (78.1%) isolates were reduced to more than 1/2 of MIC value before the reserpine addition. These results demonstrated that efflux pump lde may be an important factor in mediating quinolone resistance, but the resistance level may be determined by the expression of lde gene in Listeria monocytogenes. The 32 isolates belonged to 10 sequence types (STs) by multilocus sequence typing, ST8(serogroup I.1), ST9(serogroup I.2) and ST87 (serogroup II.2) were predominant in quinolone-resistant isolates, which posed a potential public health risk to consumers.