Mixed metal oxide containing iron with the high-sulfur capacity and reactivity is considered as one of the most favorable sorbents for desulfurization in hot gas. The stability and life of iron-based sorbents are the main challenges for the hot gas cleanup techniques. Not only the effect of gas atmosphere but also the effect of ZnO and MgO on the stability of iron-based sorbent was studied in this work. The mechanism and factors influencing sorbent stability are discussed. The results showed that the coexistence of CO and H-2 result in the instability of the zinc-iron-based sorbents. ne reaction of carbon deposit is the crucial step affecting the stability of sorbent for hot gas desulfurization. ZnO in the sorbent is adverse to the physical stability of the iron-based sorbents. MgO in the sorbent hardly affects the physical stability of the iron-based sorbents but improves the capacity of removing the hydrogen sulfide from hot coal gas at 773 K.