To study the efficacy and possible pharmacodynamic mechanism of Xiao'er Jiebiao Oral Liquid in A549 infected with H1N1.Methods:The cytotoxicity test and antiviral test of Xiao'er Jiebiao Oral Liquid with different concentrations on A549 were carried out，and the half cytotoxic concentration(TC50)，half cell inhibition concentration(IC50)，and therapeutic index(TI) of the drug were obtained by the MTT method combined with the CPE method.The indirect immunofluorescence method was used to detect the changes in neuraminidase after Xiao'er Jiebiao Oral Liquid acted on A549 infected with H1N1.The effect of Xiao'er Jiebiao Oral Liquid on the expression of interferon-α(IFN-α) and interferon-β(IFN-β) in the A549 virus model was detected by enzyme-linked immunosorbent assay.Results:It was shown that TC50=2.31 g/L，IC50=0.49 g/L，and TI=4.71 in Xiao'er Jiebiao Oral Liquid.Compared with the model group，the Xiao'er Jiebiao Oral Liquid group reduced the expression of influenza virus neuraminidase at 24 h，48 h，and 72 h.At 24 h，48 h，and 72 h，the release of A549 IFN-α and IFN-β in the Xiao'er Jiebiao Oral Liquid group was reduced compared with the model group(P<0.05).Conclusion:Xiao'er Jiebiao Oral Liquid has a curative effect on A549 infected with H1N1，reducing the expression of IFN-α and IFN-β，which may be the mechanism of the curative effect.