Abstract Catalytic property of Pd/Fe₂O₃ catalysts on carbon monoxide (CO) oxidation at low temperature were investigated in this paper. Both the as-prepared and H₂-pretreated Pd/Fe₂O₃ catalysts show catalytic performances on CO oxidation. The CO was completely converted at 333 K for the as-prepared sample, whereas at 313 K for H₂-pretreated Pd/Fe₂O₃-573 catalyst. The catalytic performance of the Pd/Fe₂O₃ catalyst decreases with increased calcination temperature. This may be due to the increased crystallinity of the support and decreased metal-support interaction. Progressive deactivation of the catalysts during long-time reaction was associated with the formation of carbonates on the catalyst surface that inhibits CO activation or intermediate transformation.