Objective   To understand the situations of influenza epidemic as well as the aberrance of the surface proteins antigenicity of influenza virus.

  Methods   Influenza virus isolation was performed by using the erythrocy test eggs aging form 9 to 11 days or MDCK cells.The identification of virus and the verification of serum influenza antibody of hen were carried out with hemagglutinin inhibition test and semi-sensitried mircro-hemagglutinin inhibition test separately.

  Results   There was no massive influenza epidemic outbreak from the year 1991 to 2000.1008 strains were isolated in such period.A(H3N2) subtype influenza virus(62.3%)and B type influenza virus(26.6%)was in dominance.10 strains of H9N2 subtype of birds influenza virus were isolated form human groups.98 strains of H9N2 birds influenza virus were isolated form chickens.The antigenicity of A(H3N2)subtype virus were floating continuously.

  Conclusion   Subtype of A(H1N1)could not be isolated in the year 1993 and 1995, but A(H1N1), A(H3N2)and B type influenza virus could be isolated contemporary during the rest 8 years.Subtype of H9N2 birds influenza virus could be isolated both in the year 1998 and 1999.The variation in surface antigen of A(H3N2)subtype could be confirmed.There were couples of A subtype of influenza viruses occurred temporary in chickens.It was necessary to carry out influenza inspection.