Abstract: The diffusion couple method was used to study the solid-state reaction of the Fe₂O₃-TiO₂ system in the temperature range of 1323 K to 1473 K in argon. The microstructure of the diffusion couple and the diffusion concentration profiles of Fe and Ti were determined by electron probe microanalysis (EPMA). According to kinetic analysis, this solid-state reaction is controlled by the diffu-sion of Fe, Ti and O ions. The inter-diffusion coefficient, which increases with the increasing temperature and concentration of Ti ions, was calculated by the Boltzmann-Matano method, and its order of magnitude is in the range of 10^-13 to 10^-10 cm²·s^-1. The diffusion activation energy (about 356.06 kJ·mol^-1) of the system in argon is much bigger than that in air, which indicates that the partial pres-sure of oxygen in atmosphere has important effect on the reaction mechanism of the system.