Abstract: ObjectiveTo develop avian influenza(H5N1)vaccines used in human body.To establish the virus seed bank used to produce avian influenza vaccines according to "Requirements for Bacterial and Viral Strains-Seeds Used for Production and Quality Control of Biologics" from the book called PHARMACOPO EIA OF THE PEOPL E'S REPUBL IC OF CHINA Volume Ⅲ.MethodsTo importe from abroad and checked up entirely the two-virus seeds of R1194 and R1203 for the avian influenza vaccine production.To establish three virus seed lot systems(seed bank)i.e.the primary seed lot,master seed lot and working seed lot.ResultsThe two seeds of avian influenza vaccines can be multiplied greatly and passaged steadily in egg embryos;The cross hemagglutinin-inhibiting test and immunodiffusion test with the antigen and antibody of human influenza A1,A3 and B and avian influenza H5N1 indicated that the above two seeds had the character of avian influenza H5N1.The complete HA genes,that were sequenced,approved that the seeds were avian influenza H5N1 viruses.The virulence genes were deleted and the two seeds belonged to feebleness virulence strain by sequence compared with wild types.The two seeds,which were passed 2,4 and 5 times in egg embryos respectively,were confirmed as the primary seed lot,master seed lot and working seed lot.ConclusionThe two-virus strain R1194 and R1203 imported from abroad can be used to produce the avian influenza vaccines.