〔Abstract〕 Objective To prepare liposomes of egg yolk antibodies againstPorphyromonas gingivalis(anti-Pg-IgY liposome), and to study the antibacterial effect of these anti-Pg-IgY liposomes onPorphyromonas gingivalis, a major periodontal pathogen. Methods Anti-Pg-IgY liposomes were preparedby thin film dispersion. Use transmission electron microscope to observe the appearance and characterization of anti-Pg-IgY liposomes.Zeta potential(ζ-potential) and particle size of anti-Pg-IgY liposomes was determined by ultrafiltration centrifugation method. The micro-liquid dilution method was used to study the minimum inhibitory concentration(MIC) and minimum bactericidal concentration(MBC) of anti-Pg-IgY liposomes against Porphyromonas gingivalis and draw its kill-time curve. Results The average particle size of the liposomes was(175.43±3.25) nm(n=4), while the polydispersity index was 0.263(n=4), and the zeta potential was(-37.82±0.20) mV(n=4). The encapsulation efficiency was 42.71%(n=4), and the cumulative release rate was 83.4%. The MIC and MBC values of the Pg-Igy liposomes against porphyromonas gingivalis were 4 mg/ml and 8 mg/ml, respectively. When the anti-Pg-IgY liposome reached the MBC value of bacteria, it could completely inhibit the growth and reproduction of bacteria in the culture medium. Conclusion The anti-Pg-IgY liposomes exhibit excellent antibacterial activity, and can kill the bacteria when the minimum germicidal concentration is reached.