〔Abstract〕 Objective To investigate the inhibitory effect of MTAN on peri-implant inflammatory bacteria and biofilm. Methods Different concentrations of Nisin MTAN, MTAN+EDTA were used to treatP.gingivalis,F.nucleatumandS.sanguinis. Chlorhexidine and sterile water were used as negative and positive controls, respectively. The OD value was used to measure MIC and MBC. Biofilm ofF.nucleatumwas established by cementum sheet. Biofilm morphology was observed by scanning electron microscopy under different concentrations of the reagents and effect. Results MTAN forS.sanguinis,F.nucleatum,P.gingivalis, of MIC were 31.3,62.5 and 125 μg/ml while MBC were 125,250,500 μg/ml. MTAN+EDTA MIC of three kinds of bacteria were 31.3,31.3,62.5 μg/ml while MBC were 125,62.5,250 μg/ml. OD values displayed above the MIC of each group were significantly different(P<0.05) with the negative control group. Conclusion Both MTAN and MTAN+EDTA had strong inhibitory effects on the pathogenic bacteria of peri-implant inflammation, among which MTAN+EDTA had stronger inhibitory effects onP.gingivalisandF.nucleatum. The inhibition of MTAN and MTAN+EDTA on the biofilm formation ofF.nucleatumincreased with the increase of Nisin concentration.