Peptide growth factor receptors are membrane-bound glycopeptides that regulate the action of peptide growth factors on their target cells. Their peptide backbones could be divided into three segments: extracellular region, transmembrane region and intracellular region.According to the structural characteristics in these regions, especially the existence of protein kinase domain in the intracellular region, a new method of peptide growth factor receptors classification is postulated. The signal transduction pathways of these receptors are also compared.