Abstract: In order to further study the activation mechanism of silver ions on sphalerite, the Ag⁺ substitution and adsorption mechanism on sphalerite were studied by density functional theory. Meanwhile, the activation effect of silver to the adsorption of xanthate on sphalerite was studied. The results showed that ethyl xanthate did not interact with the un-activated sphalerite surface but could have strong interaction with the Ag⁺-activated sphalerite surface. Compare with the two activation models, Ag⁺ adsorption activation was more likely to occur in terms of energy than Ag⁺ substitution activation. On the Ag⁺ substitution-activated sphalerite surface, the S atom of xanthate interacted weakly with surface Ag atom, while on the Ag⁺ adsorption-activated sphalerite surface, the S atom of xanthate interacted strongly with surface Ag atom. Density of states analysis showed that on Ag⁺ adsorption-activated sphalerite surface, the 3p state of S atom and the 4d state of Ag atom had many overlapping regions of bonding orbital electron clouds. This indicated that adsorption-activated Ag⁺ had a strong interaction with S atom of xanthate. Mulliken charge analysis showed that there was more charge transfer between the Ag⁺ adsorption-activated sphalerite surface and xanthate, which further indicated that Ag⁺ adsorption-activation was more likely to occur.