Legionella pneumophila (L. pneumophila) is a facultative intracellular pathogen which can cause Legionella pneumonia and Pontiac fever, it mainly infects amoeba and human macrophages, it can escape lysosomal degradation by relying on the effector protein produced by Dot/Icm IVB secretion system in host cells. In this paper, the pathogenic substances, intracellular survival and proliferation mechanism of L. pneumophila as well as biological function of its effector protein were reviewed, the virulence factors and pathogenesis of L. pneumophila were introduced in detail, which provide new ideas for the study of prevention and treatment of Legionella disease, and also provided important reference for the study of infectious diseases caused by other intracellular pathogens.