The OCA2 gene is an important mammalian pigment gene that is involved in the melanin synthe-sis reaction, and is also a main regulator of human eye color. It encodes a 110 kD-sized transmembrane protein, which is located at the melanosome vesicle membrane. Studies have shown that OCA2 affects the melanin synthesis through regulating maturation and pH value of melanosomes, and participating in the first step of the melanin synthesis pathway. The rs12913832 enhancer of the adjacent gene HERC2 modulates the expression level of OCA2 to ultimately control human eye color. In addition, OCA2 is also the causative gene for oculocutaneous albinism typeⅡ(OCA2) and has indirect effects on diseases including Prader-Willi syndrome (PWS), Angelman syndrome (AS) and melanoma, with which patients usually show hypopigmenta-tion of skin or hair. Herein, the research progress of the OCA2 gene from the perspectives of molecular bio-logy, cell biology and genetics is reviewed, so as to provide novel ideas for further exploring the molecular mechanisms of OCA2 and the diagnosis and treatment of the related diseases.