Abstract: Objective To develop a specific and sensitive molecular biological method for rapid detection of influenza virus.Methods Multiplex reverse transcription-PCR and half nested multiplex-PCR were used to amplify and differentiate the hemagglutinin(HA)genes of influenza virus subtypes of H₁ and H₃ and type of B.Results Three primer pairs are specific for the influenza virus subtypes of H₁ and H₃ and type of B.And their HA gene amplicons are particular in size.The amplicon of H₁,H₃ and B are 942bp 1117bp and 751bp in size respectively.The type and subtypes of influenza virus can be detected according to the size of HA gene amplcon.The influenza virus can be detected in a 0.1 TCID₅₀ specimen.Conclusion Muitiplex reverse transcription-PCR and half nested multiplex-PCR are specific and sensitive molecular biological methods for rapid detection of influenza virus.