While Fe-based oxygen carriers (OC) are regarded to be promising for chemical looping combustion (CLC), the decrease of CO2 selectivity during deep reduction process and the severe agglomeration of Fe 2 O 3 often occur after multiple redox cycles due to the low oxygen mobility. Herein, Fe-substituted Ba- hexaaluminates (BaFe x Al 12–x O 19 , denoted as BF x A-H, x = 1 and 2) prepared by a modified two-step method exhibited not only higher amount of converted oxygen (O t ) and CH 4 conversion (77% and 81% vs. 17% and 75%) than those prepared by the traditional co-precipitation method (BF x A-C, x = 1 and 2) but also high CO2 selectivity above 92% during the nearly whole reduction from Fe 3 + to Fe 2 + . Furthermore, the BF x A-H exhibited the excellent recyclability during 50 cycles. The better performance was ascribed to the markedly enhanced oxygen mobility which resulted from dominant occupancy of Fe cations in Al(5) sites (Fe 5 : 71% and 70% vs. 49% and 41%) in mirror planes of hexaaluminate leading to larger amount of lattice oxygen coordinated with Fe 5 (O –Fe 5 ) (0.45 and 0.85 mmol/g vs . 0.31 and 0.50 mmol/g). The improvement of oxygen mobility also favored the preservation of chemical state of Fe cations in hexaaluminate struc- ture in the re-oxidation step, resulting in the excellent recyclability of BF x A-H.