The transforming growth factor β2(TGF-β2) precursor protein consists of 19 amino acid signaling peptide, 283 amino acid precursor region and 112 amino acid maturation region. The homology of human TGF-β2 mature region with human TGF-β1 and TGF-β3 was 71% and 80%, respectively, and the homology with mouse TGF-β2 was 97%. It can be expressed by a variety of cells, including osteoclasts, thymus epithelial cells, keratin cells, hepatocytes, gastric master cells and satellite cells. TGF-β2 has significant cross-species biological activity, such as human TGF-β2 has activity on mouse cells, while pig TGF-β2 has activity on rabbit cells. TGF-β2 has four basic activities: it is a growth inhibiting factor for most cell types; Can enhance extracellular matrix deposition; It can inhibit the expression of IL-12 and CD40L in antigen-presenting cells and up-regulate the secretion of IL-10. It is expressed in discrete regions during embryonic development, such as epithelium, myocardium, cartilage and bone of hands and feet, and nervous system, suggesting that it has a specific function.