The insulin-like growth factor binding proteins(IGFBPs)are a family of soluble proteins that bind the insulin-like growth factors(IGFs) with high affinity.These proteins not merely carry the IGFs and prolong the half-life of IGFs,but have influences on both the bioactivity and distribution of IGFs in the extracellular environment.Under the different experiment conditions, IGFBPs can either inhibit or augment IGFs actions. In addition, IGFBPs appear to have intrinsic biological activity independent on IGFs. Research on molecular structure,gene expression, post-translational modifications, and bioactivity of IGFBPs were summarized.