The present invention provides monoclonal antibodies that bind specifically to H5 subtype avian influenza virus hemagglutinin (HA) proteins, and can block the binding activity of at least 50% of the known monoclonal antibodies to the H5 subtype avian influenza virus hemagglutinin (HA) protein. The monoclonal antibodies can be used for the detection, diagnosis, prevention, and treatment of avian influenza viruses, especially the H5 subtype of avian influenza viruses. The present invention also provides the related hybridoma cell lines, isolated nucleic acid molecules and short peptides, as well as medical composition and medical diagnostic equipment and kit containing the monoclonal antibody.
