Abstract: The authors summarized the biological chain transfer and dose estimation of radionuclide tritium entering the body. Tritium in nature or released during nuclear energy operation can enter the body through the respiratory tract, gastrointestinal tract, skin and mucosa, and others, and be transferred to various tissues and organs in the body through the blood. The authors focused on reviewing the rule on distribution, metabolism, retention and discharge of tritium within the body, as well as the transfer of tritium water in pregnant, lactating, fetal and postnatal mouse, the dose estimation due to internal exposure to tritium, and the calculation of the mean absorbed dose at the tritium containong cellular level. In order to provide a reference for more accurate assessment of the biological effects and radiation risks associated with tritium in the future.