Influenza A virus (IAV) is the dominant type of seasonal influenza and is also an important viral agent of acute respiratory tract infections in children worldwide. Nonstructural protein 1 (NS1) is a protein encoded by viral genome, expressed in the infected cells but not in virions. In recent years, large number of studies have shown that NS1 is an important virulence factor of IAV. NS1 plays multiple roles in antagonizing host antiviral response, inhibiting host cell apoptosis, and modifying host and itself gene expression via NS1-RNA and NS1-protein binding. In-depth study on interaction between NS1 and host cells can not only deepen the comprehending of the pathogenesis of IAV, but also lay a theoretical foundation for the prevention and control of IAV. It also has important application value in the development of new antiviral drugs and vaccines.