Abstract: This paper presents methods of preparing platinum/polystyrene divinyl benzene (Pt/SDB) hydrophobic catalyst for hydrogen isotopic exchange between water andhydrogen. Specific surface of the support is more than 400m2/g. Two approaches of reduction are used for platinum dispersion and comparison is made with each other. Platinum particles obtained by reduction of hydrazine hydrate are smaller. Particles obtained by reduction of hydrogen are larger and their shapes of boundary are unclear. Dispersion of platinum on the support decreases with increasing the amount of platinum. When the amount of platinum is increased to 4 percent, granules of platinum exist as colony. The T-H catalytic exchange at 30℃, 50℃ and 70℃ has been measured. The activity at 50℃ is the best. Optimum amount of platinum on the SDB is between 0.5% to 1.5%.