Metapneumovirus, including human metapneumovirus and avian metapneumovirus, is an important pathogen in human and avian infections. The attachment protein is one type of glycoprotein on the surface of metapneumovirus particles, which belongs to type Ⅱ transmembrane protein. Compared with other paramyxoviruses, the length of the amino acid sequence, the homology and the biological functions (such as the attachment of the virus, the mediation of cell fusion, the influence of viral replication in cell culture and in vivo, and the immuno-protective effect) of the G proteins of metapneumovirus are different. Meanwhile, the G protein of metapneumovirus plays an important role in immunosuppression and immune evasion. At present, few related research has been carried out in China. The aim of this paper is to review and discuss the latest research and progress in the study of the attachment proteins of metapneumoviruses. The future research direction is prospected.