Objective To understand the antigen difference of influenza A(H_3N_2) viruses isolated in two outbreaks in the same area simultaneouly. Methods Viral RNA was extracted from the viruses isolated in MDCK and transcribed into cDNA by reverse transcriptase and amplified by PCR.The PCR product was purified and determined nucleotide sequence.Results The pathogen for the two outbreaks were influenza A(H_3N_2) virus.But farther analysis with nucleotide sequence showed that the antigenic of influenza A(H_3N_2) virus...