The present invention relates to an antiviral application of nucleoside analogs. Specifically, the present invention relates to uses of nucleoside analogs and a pharmaceutical composition thereof as: (a) inhibitors for inhibiting the replication of coronaviruses, influenza viruses, respiratory syncytial viruses, flaviviridae viruses, filoviridae viruses and/or porcine epidemic diarrhea virus (PEDV); and/or (b) medicines for treating and/or preventing and mitigating diseases caused by coronavirus, influenza virus, respiratory syncytial virus, flaviviridae virus, filoviridae virus and/or porcine epidemic diarrhea virus (PEDV) infections. The nucleoside analogs according to the invention may treat and/or prevent and mitigate respiratory infection, pneumonia (COVID-19) and other related diseases caused by 2019 novel coronavirus infection.