The invention discloses a recombinant influenza
virus vector carrying foreign genes in an NA segment, which can be rescued in cells by a
virus rescue method and can be amplified in
chick embryos in large quantities. The invention also discloses a preparation method thereof, comprising the following steps: firstly constructing plasmids used for rescuing influenza viruses and introduced with the foreign genes on the NA
genome segment of the influenza
virus and carrying out rescue on host cells. The foreign
gene is connected with the NA
genome segment by a 2A segment. The foreign
gene comprises EGFP reporter genes and adopts a CMV / huPolI bidirectional influenza virus rescue
system. The recombinant influenza virus vector overcomes
capacity limit of the foreign genes in the influenza virus
genome, enjoys stable passage in
chick embryos, can be applied to vaccine and
drug development and tumor treatment and can produce recombinant
cell factor drugs in cheap chick
embryo bioreactors.