Chemical looping methane reforming (CLMR) is a promising technology for syngas generation by designing an oxygen carrier to partially oxidize methane into mixed gases with expected H-2/CO ratio. The major challenge is the development of oxygen carriers with high reactivity, good selectivity, and excellent recyclability. We investigated a novel interstitial doped perovskite as an oxygen carrier to regulate the oxidation activity and demonstrated that Mg ions that interstitial entering into the crystal lattice of perovskite can improve the activation of methane greatly without any change of the crystal structure. According to the results of XPS and H-2-TPR, Mg ions also reduced the electron binding energy of oxygen on the sample surface and increased the migration rate of lattice oxygen. Compared with LSFC and Li-LSFC, the interstitial doping Mg-LSFC exhibited higher average methane conversion up to 98.66%, accompanying with 78.15% hydrogen content. Furthermore, the average yield of hydrogen of Mg-LSFC increased from 1.60 ml to 2.25 ml per 1 ml of methane when 0.02 g/min water participated in the reaction. Besides, the stability of Mg-LSFC was also proved by thermogravimetric experiments and fixed bed pulse experiments. Based on the experiment results, the reaction mechanism for methane activation was discussed to further providing a pathway to effectively enhance the hydrogen-rich syngas generation. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.