Periodontitis, one of common oral diseases, was the main reason for tooth loss of adults in our nation. Porphyromonas gingivalis（P.gingivalis） played an important role in periodontal tissue destruction, and became one of the focuses in domestic and foreign scholars’researches in recent years. This review focused on the researches of the relationship between P.gingivalis and oral diseases, relationship between P.gingivalis and systemic diseases, genome and pathogenicity genes of P.gingivalis, and interaction between P.gingivalis and gingival epithelial cells. This review intends to broaden the view on the researches of P.gingivalis, furthermore, to provide a new objective for periodontal therapy.
