Experiments were performed to obtain detailed adsorption and desorption characteristics of tritium (HT) by Cryogenic Molecular Sieve Bed (CMSB) in liquid nitrogen temperature under the simulated Breeding Blanket Interface (BBI) condition. Computer simulation analyses gave the values of separation factor and mass transfer coefficient of HT in H2, which are very important basic parameters for the optimum design of CMSB process in BBI.