Abstract: Hydrogen isotopes, such as protium(H), deuterium(D), and tritium(T), are widely used in medical treatment, nuclear energy, national defense, and other fields. Under the background of the "double carbon" target with carbon peak and carbon neutralization, deuterium-tritium fusion energy is considered to be an important energy strategy in China. However, the relative abundance of deuterium and tritium in nature is extremely low, and it is of great significance to separate hydrogen isotopes economically and effectively. This paper presents the research on water hydrogen isotope separation technology. Firstly, the methods and the principles of hydrogen isotope separation in water are summarized. Then, two perspectives of separation methods were reviewed. From the perspective of engineering application, the electrolysis, distillation and chemical exchange method are focused. From the perspective of laboratory research and development, the membrane separation method and porous material adsorption method are focused. Finally, the separation factors and energy consumption of typical separation technologies are compared. Moreover, to provide a certain reference for the water hydrogen isotope separation technology, several future research directions are prospected.