Abstract: The technical characteristics of rocket upper stages at home and abroad are compared,and key cryogenic fluid management techniques are summarized and present. The space thermal insulation techniques,on-orbit gas-liquid separation techniques,on-orbit venting techniques associated with cryogenic propellant are reviewed and analyzed. It is pointed out that applying up-to-date thermal insulation techniques,the cryogenic propellant could be stored safely for longer time and thus the upper stage could provide a wider application range. Besides,use of thermal insulation,structure optimization design of upper stage,and fluid management techniques comprehensively is beneficial to reduce the boil-off of cryogenic propellant in space. Comparatively,metal screen capillary gas-liquid separation device is more suitable for the pure-liquid acquisition of cryogenic liquid,especially in liquid hydrogen tank. Moreover,traditional thermodynamic venting system(TVS)could realize the purpose of pure-gas venting in space,but extra propellant boil-off is yielded. Instead, a passive TVS could be suggested for the gas venting of cryogenic tank. In a word,more attention should be given in the researches on fluid science and management techniques of liquid hydrogen in space,and liquid hydrogen/liquid oxygen propellant upper stage should be developed as soon as possible.