The invention discloses a meroterpenoid compound and a preparation method and applications thereof, and belongs to the technical field of marine fungus active component analysis. The molecular formulaof the meroterpenoid compound is C25H34O5. The preparation method comprises following steps: inoculating activated Talaromyces purpureogenus CX11 to a culture solution, carrying out fermentation culture; performing separation to obtain mycelia and fermentation broth, adding mycelia into an organic solvent, carrying out extraction, then using ethyl acetate or chloroform to extract the extract; (orusing ethyl acetate or chloroform to extract the fermentation broth); concentrating the extract, and carrying out separation and purification to obtain the meroterpenoid compound. The meroterpenoid compound is extracted and separated from fermentation culture of Talaromyces purpureogenus CX11, has a novel structure and good antivirus activity, can be used to prepare antivirus drugs and health-care food for preventing viruses, and has a good development prospect.