The invention discloses an application of fidaxomicin in preparing medicines for treating related diseases and/or symptoms caused by dengue virus infection. The fidaxomicin, as a clinically approved drug for resisting clostridium difficile infection, is high in safety; and in addition, the fidaxomicin, which is high in activity of inhibiting the dengue virus infection and relatively strong in binding capacity with dengue virus non-structural protein NS5, is expected to function as a novel drug for resisting the dengue virus infection.