Abstract: In order to cliarify the kinetics of oxygen transfer in metallurgical gas-solid reactions, the oxygen isotope exchange technique was used to study the oxygen exchange reaction between CO₂-CO gas containing ¹⁸O and iron oxide at 1373 K. The influence of oxygen partial pressure on oxygen exchange reaction was investigated. The results show that the rates sharply decrease approximately 100 s, and then gradually decrease with the reaction time proceeded. The rate-limiting step changes from interfacial chemical reaction in the initial stage to mass transfer in the following stage. Higher oxygen potential in mixture gas accelerates the oxygen exchange reaction.