Abstract: ObjectiveTo investigate the epidemic characteristics and etiological distribution of adult patients with community-acquired pneumonia(CAP)in Taiyuan,and to povide scientific basis for constituting preventive strategies and measures.Methods243 cases of CAP patients were collected in Taiyuan from Dec.2006 to Dec.2007.On the spot investigation and laboratory detection methods were used in the research.The pathogenic detection included tens of pathogen like streptococcus pnenmoniae,pneumonia mycoplasma IgM antibody,pneumonia chlamydia IgG antibody and legioella-DNA,etc.ResultsThe majority of adult CAP patients in Taiyuan were the elderly people,soldiers and migrant workers from rural areas.Its epidemic senson was in winter and spring.Three most important pathogens for CAP were streptococcus pneumoniae,pneumonia mycoplasma and legionella.The streptococcus pneumoniae was highly resistant to penicillin and macrolides,buthighly sensitive to the third generation cephalosporin and glycopeptide antibiotics.ConclusionThe streptococcus pneumoniae is the main pathogen for CAP and atypical pathogens especially pneumonia mycoplasma play important roles in CAP in Taiyuan.The mixed infection of bacteria and atypical pat hogens can't be ignored.