Abstract: The commercial operation indicated that the formation of Zinc Silicate is one of the key reasons for the deactivation of S Zorb sorbent. The commercial used sorbents in different state are tested under simulated industrial conditions with different atmospheres to investigate the relations of Zn2SiO4 formation with atmospheric environment and the silicon source. The results show that it is difficult to form Zn2SiO4 in fresh sorbent in simply dry or water vapor atmosphere even at 550℃. While Zn2SiO4 appears when the spent sorbent or regenerated sorbent coexists with the fresh one under hydrothermal condition at this temperature. The collaboration generated between SO2 produced during calcination of ZnS and high temperature hydrothermal surrounding will promote the formation of Zn2SiO4. The results also show that in the atmosphere of hydrothermal and acid, the more S in the spent sorbent, the more Zn2SiO4 formed. The growth rate of Zn2SiO4 will increases if Zn2SiO4 already exists in the spent sorbent. Different Si source will cause a different trend in the formation of Zn2SiO4, where the structured Si sources possess stronger resistance to hydrothermal-acid environment. Key words：S Zorb sorbent；Zinc Silicate；acid atmosphere