The effective tritium recovery system should be designed to recover tritium from DT reactor blanket sweep gas in a form easy to transfer to the main fuel cycle. The cryosorption method using a porous adsorbent at the temperature of liquid nitrogen is one of the candidate processes for extracting tritium from hydrogen-swamped helium sweep gas because it has advantages of a large recovery capacity of gaseous tritium and good releasability of recovered tritium to the next process. In order to quantify the performance of the cryosorption method in recovering hydrogen isotopes from hydrogen-swamped helium sweep gas flow, the adsorption capacity and separation factor for multicomponent hydrogen isotope mixtures in helium on molecular sieve 4A (MS4A), molecular sieve 5A (MS5A) and activated carbon at 77.4 K were measured.