The non-isothermal reduction kinetics and mechanism during the vacuum carbothermal reduction of ilmenite concentrate were investigated by X-ray diffraction, backscattered electron imaging, energy-dispersive X-ray spectroscopy and FactSage 7.2 at temperatures ranging from 1000 °C to 1400 °C. The quick reduction reaction appeared at 1200 °C–1300 °C and slowed down after 1300 °C. At 1200 °C, magnesium was dispersed throughout the sample, and silicon, calcium, and aluminum were dispersed and distributed in the same region. At 1350 °C, magnesium began to gather and show the same distribution as those of silicon, calcium, and aluminum. The reduction process was mainly FeTiO3→FeTi2O5→Ti3O5→Ti2O3. During the reduction process, the iron continued to nucleation, aggregate and grow, and the high-valence titanium was reduced to low-valence titanium and gradually enriched. Comprehensive consideration of Šatava–Šesták method and Coats–Redfern method, the apparent activation energy of the reduction process was 233.16 ± 8.40 kJ/mol.