The invention discloses an antiviral oral spray and a preparation method thereof. The antiviral oral spray is prepared from the following components in parts by mass: 13 to 25 parts of honeysuckle flower, 13 to 25 parts of radix scutellariae, 13 to 25 parts of fructus forsythiae, 12 to 22 parts of folium isatidis, 6 to 11 parts of liquorice root, 5 to 10 parts of radix bupleuri, 5 to 10 parts of flos chrysanthemi indici, 5 to 10 parts of radix isatidis, 0.2 to 0.8 part of menthol, 5 to 10 parts of herba houttuyniae, 1.0 to 2.0 parts of sucralose, 0.25 to 0.85 part of 95% benzalkonium bromide, 400 to 600 parts of ethyl alcohol, and the balance purified water, wherein the total amount is 1000 parts. The antiviral oral spray has the advantages that the functions of killing and inhibiting viruses in oral cavity are realized, and the killing rate on staphylococcus aureus and pseudomonas aeruginosa reaches 99.999% within 5min; the average killing logarithmic time on candida albicans is longer than 4.00min, and the killing rate is also higher than 99.99%; and the oral inflammation and respiratory tract epithelial mucosa injury caused by virus replication can be prevented, the spreading of droplets with viruses is effectively prevented, and the function of preventing the spreading and diffusion of novel coronavirus is effectively realized.