Abstract: Porphyromonas gingivalis is regarded as one of major putative periodontopathic bacteria in the bacterial etiology study, which plays a significant role in the generation and development of periodontitis. Pathogenicity islands are foreign DNA taken up via horizontal gene transfering by pathogenic microorganism, which are closely related to the bacterial virulence. In this paper, research progress on pathogenicity islands of Porphyromonas gingivalis was reviewed.