Objective:To explore the inhibitory effects of Mentha haplocalyx Briq. With different extraction methods on respiratory syncytial virus (RSV) in vitro and antiviral mechanism of it seffective parts. Methods:By using the virus infection model in vitro to detect the cytopathic effect (CPE) of the anti-RSV effect of Mentha haplocalyx Briq. in vitro. Make the anti-RSV therapeutic index (TI) in vitroas the index to screen the extraction method of mint and the macro-porous adsorption resin, so as to determine the best extraction method, and the best macroporous adsorption resin was used for separation and purification. Elution with different concentrations of eluent was used to determine the effective parts of Mentha haplocalyx Briq. resisting RSV. The antiviral mechanism was analyzed by different administration methods. Results:The supernatant of Mint after water extraction and alcohol precipitation had the strongest inhibitory effect on RSV, with TI value of 37.58; HPD100 resin had the best separation and purification effect on the supernatant, and 25% ethanol elution site had the best effect, and the TI value was 57.8. The effective substances were determined to be polyphenols by physicochemical identification reaction. After the effective parts are mixed with the virus, the antiviral experiment is the best.Conclusions:The supernatant of mint after water extraction and alcohol precipitation was adsorbed by HPD100, and 25% ethanol eluent had the best anti-RSV effect, with preventive and therapeutic effects.