Abstract: A kind of high-temperature-resistant adsorbent for radioiodine, AgNbO₃/Al₂O₃, was synthesized with the method of mechanical mixing. Compared with traditional silver adsorbent (Ag/Al₂O₃), AgNbO₃/Al₂O₃ adsorbent shows more stable performance at high temperatures. Particularly, the decontamination factor of this adsorbent is far more than that of traditional silver adsorbent at temperatures higher than 650 ℃. Characterization data show the structure of the adsorbent is stable, and it can endure longtime hightemperature calcination. Results of thermogravimetric analysis and iodine desorption indicate that the enhancement of stability of silver iodine on AgNbO₃/Al₂O₃ adsorbent is the reason why AgNbO₃/Al₂O₃ adsorbent has better performance at high temperatures. This adsorbent may be used in nuclear accident for emergency disposal.