The floating sealing ring is the key shaft seal of the hydrogen-cooled turbogenerator,and improving its floatability can effectively reduce the hydrogen consumption and improve the operating reliability of the generator.Three typical products in the development process of shaft end seal of hydrogen cooled generator were reviewed,the disc sealing ring,the circumferential sealing ring and advanced floating sealing ring,such as segmented carbon sealing ring.The structural characteristics and working principles of various floating sealing rings were briefly described.The key influencing factors on the floatability of sealing ring and hydrogen consumption were analyzed.The innovative design scheme and applicable conditions of various sealing ring structures and seal oil system aiming at improving the floatability and reducing the hydrogen consumption were emphatically discussed,it provided reference for the technical research and engineering application of hydrogen cooled turbine generator shaft end seal.