The chemical looping conversion of CH 4 has been one of the most promising technologies for achieving the "twocarbon" strategy. Fe 2 O 3 oxygen carrier cannot maintain the excellent release performance of lattice oxygen at high temperature due to the sintering and carbon deposition. Therefore, quaternary La 1−x Sr x Fe 1−y Co y O 3 perovskite was selected as the transfer support of oxygen ions. By using the MOF precursor method, ternary La 0.8 Sr 0.2 FeO 3 was prepared via the introduction of metal Sr into the binary LaFeO 3 . The adsorption energy of CH 4 on the La 0.8 Sr 0.2 FeO 3 was the lowest (−0.054 eV), compared with separate Fe 2 O 3 and LaFeO 3 , and the adsorption energy of free H at the adjacent Fe site was the lowest (1.650 eV). Furthermore, the La 1−x Sr x Fe 1−y Co y O 3 perovskite was successfully synthesized by the doping of Co into the ternary La 0.8 Sr 0.2 FeO 3 . La 0.8 Sr 0.2 Fe 0.8 Co 0.2 O 3 was chosen to composite Fe 2 O 3 oxygen carrier. As m(Fe 2 O 3 ):m(La 0.8 Sr 0.2 Fe 0.8 Co 0.2 O 3 ) = 1:1, the lattice oxygen conversion rate was less than 47% and the selectivity of CO 2 reached 99.5% through the synergistic effect of lattice oxygen and oxygen vacancies. Fe 2 O 3 −La 0.8 Sr 0.2 Fe 0.8 Co 0.2 O 3 increased the lattice oxygen conversion by 17.6%, compared with Fe 2 O 3 −La 0.8 Sr 0.2 FeO 3 . After the CH 4 chemical looping conversion cycles five times, Fe 2 O 3 −La 0.8 Sr 0.2 Fe 0.8 Co 0.2 O 3 still had favorable structural stability and oxidation performance, and the lattice oxygen conversion rate still reached >95%.