Abstract: The irradiation stability of Pt-SDB(SDB, styrene-divinylbenzene copolymer)， Pt-PTFE(PTFE, polytetrafluoroethylene)， Pt-C-PTFE were preliminary investigated. These catalysts were immersed in tritiated water(HTO) whose ³H concentration is 1.26×10¹²Bq/Lfor 210 d. The chemical composition of the gaseous phase over the catalystHTO system is analyzed by GC-MS. The residual tritium in the catalyst after 210 d immersion is measured. The catalytic activity of these catalysts towards ³H isotope exchange reaction before and after immersion in HTO is evaluated by determination of the conversion ratio of ³H. The experimental results show that no noble irradiation decomposition is observed for all these three catalysts. The residual amount of ³H in the catalysts after the experiment is found to increaseas their specific surface area increases, but the substitution of ³H for H or F is negligibly small. However, variation does occur to different extent. No appreciable variation in conversion ratio is detected in the cases of Pt-PTFE and Pt-C-PTFE,while a decrease of 11.2%and 16.9% is observed in the case of Pt-SDB(1) and Pt-SDB(2), respectively.