In order to investigate the phenomenon that the affecting mechanism of high-titanium vanadium-titanium magnetite is caused by separate TiO₂ or by CaTiO₃ formed from TiO₂ and CaO, calcium ferrite was synthetized by pure reagents of Fe₂O₃ and CaO, and the effect of TiO₂ and CaTiO₃ on the formation mechanism of titanium calcium ferrite (FCT) was researched. Different samples were sintered at the temperatures of 1023~1423 K for different time under air atmosphere based on thermodynamics calculations with Factsage 7.0. The phase transformation and microstructure changes in sintered samples were examined through different characterization means including X-ray diffraction and scanning electron microscope-energy disperse spectroscopy. It is found that the formation process of calcium ferrite can be mainly divided into two stages. The synthesized product is Ca₂Fe₂O₅ with the reaction “Fe₂O₃ (s) + 2CaO (s) = Ca₂Fe₂O₅ (s)” between Fe₂O₃ and CaO at 1023~1223 K in the former stage, and the predominant product is CaFe₂O₄ with the reaction “Ca₂Fe₂O₅ (s) + Fe₂O₃ (s) = 2CaFe₂O₄ (s)” between Ca₂Fe₂O₅ and Fe₂O₃ at 1223~1423 K in the latter stage, in which the reaction rate is accelerated especially at 1423 K. It is observed that CaTiO₃ increases with increasing the temperature. However, the solid solution of Ti element in calcium ferrite is greatly difficult to realize and the reaction between TiO₂ and calcium ferrite is not an effective way to generate FCT. It is also observed that the amount of Fe element in the phase boundary of CaTiO₃ and FCT increases with the extension of the thermal insulation time. FCT is predominantly formed through the solid solution of Fe component in CaTiO₃, and the main reaction is “Fe₂O₃ (s) + CaTiO₃ (s) = FCT (s)”.