Abstract: Legionella widely exists in the nature water source. Legionella is one of the main pathogen that causes both sporadic and epidemic community-acquired pneumonia.Many countries and theareas have the report of Legionnaires' disease.Legionnaires' disease has different clinical presentation,mainly displays in pneumonia and obviously affected organ damage. The raise separation obtains the regiment Legionella strain is determines the regiment Legionella infection the goldeu standard. Union treatment of macrolides and fluoroquinolones may obtain the good effect.This aticle reviews the recent development of the epidemiology,clinical presentation,diagnostic methods,and trentment.