Abstract: ObjectiveTo explore the application of multiplex reverse transcription(RT)nested PCR in the screening of pathogens related to epidemic outbreak of acute respairatory system diseases.MethodsTotally 34 oropharyngeal swab specimens were collected from the cases of 3 epidemics of acute respiratory diseases and detected with multiplex RT-nested PCR for 23 pathogens related to the diseases.ResultsThere were 9 cases of unknown pneumonosis happened in hospital A.Chlamydia pneumoniae was detected among 66.7% of the cases.There were 13 cases of unknown pneumonosis in school B and hemophilies influenzae B was detected in 7 cases(53.8%).There were 12 cases of unknown pneumonosis in school C and hemophilies influenzae B was detected in 5 cases(41.7%).ConclusionMultiplex RT-nested PCR is a rapid and highly efficient method to screen the pathogens related to epidemic outbreak of acute respiratory system disease.