The protein encoded by gene Nhlh2 (nescient helix-loop-helix 2, also known as HEN2 or NSCL2) is a new member of basic helix-loop-helix (bHLH) transcription factor family and is specifically expressed in nervous system, especially in neuroendocrine tissue. The homologous genes of Nhlh2 have been found in many eukaryotic organisms such as chicken, mouse, rat, cattle, and human. The functional researches of Nhlh2 are mainly focused on neuroendocrine system, retina development, and tumors. Some preliminary results have been obtained in the investigation of molecular regulation mechanism. This article summarizes the recent research advances in Nhlh2.