Growth Hormone -releasing Peptide ( ghrelin) is a new found peptide recently,which distributed in various tissues including gastric,hypothalamus,hypophysis and lymph tissue.Its physiology lies in regulating the releasing of GH and other hormones,participating in the energy metabolism and affecting cardiovascular function.Recently,many study showed that ghrelin has somewhat correlation with obesity,2DM and metabolic syndrome.The article mainly talks about the study in these parts.