The platinum catalyst supported on polymer can be used in the hydrogen isotope exchange reaction applied to the tritium removal or heavy water separation processes. The effect of the procedures for the platinum loading in the preparation of Pt/SDBC catalysts on the platinum dispersion was investigated. The conventional impregnation method was used in the process of platinum loading. Drying temperature was 80℃ in air and calcination was performed at 150℃ with flowing O₂. The thermal stability of the prepared catalysts was confirmed by the experimental results of the TGA and BET. The dispersions of platinum on the polymer(SDBC) support were measured by hydrogen adsorption experiment. As the platinum loadings were increased, the platinum dispersions were decreased. The oxygen treatment at higher temperature improved the platinum dispersions of the prepared catalysts.