Parathyroid hormone-like hormone (PTHLH), also known as parathyroid hormone-related protein (PTHrP), was first identified as a parathyroid hormone (PTH)-like factor responsible for humoral hypercalcaemia in malignancies. Subsequent studies demonstrated that PTHLH has multiple physiological functions in many fetal and adult tissues, including the regulation of morphogenesis, cell proliferation and differentiation, and transplacental calcium transport. This review focuses on the biological characteristics of PTHLH and its function during embryonic development. The signaling pathway and potential mechanism involved are further discussed.