Objective:To investigate the genetic characterization (evolution,antigenicity,enzymatically active site,and glycosylation site) of the neuraminidase (NA) gene of the novel influenza virus A/H1N1 in 2009 pandemic. Methods:Genetic evolution and amino acid substitutions of the 43 NA gene sequences of influenza virus A of different years were retrieved from GenBank and were analyzed by using MEGA 4.0 software. Results:The new A/H1N1 influenza virus strains and avian H5N1 influenza virus strains had similar antigen sites of the NA genes,sharing a homology of 85%.Amino acid residues at the enzymatically active site of the NA genes were strictly conserved in all influenza virus strains,but the glycosylation sites varied. Conclusion:The NA genes of novel H1N1 influenza viruses may originate from avian H5N1 influenza virus endemic in Asia. The new H1N1 influenza viruses may respond well to the neuraminidase inhibitor treatment.