The transformation of CO2 to chemicals and fuels offers a means of CO2 utilization while mitigating the global carbon footprint. An attractive strategy involves the CO2 reforming of methane with oxygen carriers. In this strategy, methane is used as the reducing agent to provide hydrogen for CO2 reduction. This study aims to investigate the reactivity of the ilmenite-based oxygen carrier undergoing a redox reaction for CO2 reduction coupled with methane reforming and the underlying mechanism using combined experimental study and density functional theory calculations. The enhanced activity for the methane conversion and CO2 reduction with FeTiO3 was revealed under the CH4/CO2 ratio of >8.75 with CO2 conversion of >95%. The mechanistic probe indicated that the oxygen vacancies and hydrogen atoms from the successive dissociation of CH4 are crucial for CO2 activation and reduction. In the dominant formate pathway, the CO2 molecule is hydrogenated to the HCOO* intermediate species and then decomposes to CO via the C-O and C-H cleavage at the oxygen vacancy site with a low barrier of 62.5 kJ/mol. These results shed light on the fundamental understanding of hydrogen-assisted CO2 reduction over ilmenite-based oxygen carries and open up future research on potential strategies to improve CO2 utilization for redox reactions.