The composite packing with the hydrophobic platinum catalyst for the isotope exchange reaction in H2O-H2 system was improved to be appreciably active. Therefore, it bacame realistic to design a process for tritium recovery by the dual-temperature exchange method. The separation performance of dual-temperature 5-stage cascade (S3-E2) was simulated. The process was desinged to be operated under the condition of P = 0.1 MPa, TH = 70 °C, TC = 15∼20 °C. The cascade could attain tritium recovery ratio of 0.99 and enriching ratio larger than 103.