The avian flu H5Nl causes avian disease in many countries, and has already caused more than 0 billion in losses to poultry farmers. This virus genome consists of eight segments of negative-stranded RNA, which code for 11 proteins. Among them, matrix proteins (M), hemagglutinin (HA) and neuraminidase (NA) are important proteins, which are targets for vaccine production. The development of diagnostic kits for detection for avian infected with influenza A virus at early stages becomes crucial in disease control. Recently, recombinant Single Chain Fragment Variable (scFv) antibodies against pathogens in human have been produced using phage-display technology and successfully applied in developing diagnostic kits. Due to a number of advantages of this system, it is preferably powerful tool in creating kits to rapidly detect influenza A virus. In this study, the authors report effective systems for expression and purification of a scFv antibody against H5 protein of influenza A virus. The gene encoding for a scFv antibody specific for the H5 protein of influenza A virus had been previously selected and inserted into the expression vector pTI2+ (unpublished results). The scFv protein is purified by affinity chromatography principles on nickel column. And then study successfully develop a system to detect influenza A virus using the purified scFv coupling with latex beads via hemagglutination reaction.