The performance of heteronuclear cluster [AlFeO3]+ in activating methane has been explored by a combination of high-level quantum chemical calculations with gas-phase experiments. At room temperature, [AlFeO3]+ is a mixture of 7[AlFeO3]+ and 5[AlFeO3]+, in which two states lead to different reactivity and chemoselectivity for methane activation. While hydrogen abstraction from methane is the only product channel for the 7[AlFeO3]+/CH4 couple, 5[AlFeO3]+ is able to convert this substrate to formaldehyde. In addition, the introduction of an external electric field may regulate the reactivity and product selectivity. The interesting doping effect of Fe and the associated electronic origins are discussed, which may guide one on the design of Fe-involved catalyst for methane conversion.