Abstract: Hemimorphite exhibits poor floatability during sulfidization flotation. Cu²⁺ and Pb²⁺ addition enhances the reactivity of the hemimorphite surface and subsequently improves its flotation behavior. In this study, the mechanisms of Cu²⁺ + Pb²⁺ adsorption onto a hemimorphite surface were investigated. We examined the interaction mechanism of xanthate with the hemimorphite surface and observed the changes in the mineral surface hydrophobicity after the synergistic activation with Cu²⁺ + Pb²⁺. Microflotation tests indicated that individual activation with Cu²⁺ or Pb²⁺ increased the flotation recovery of hemimorphite, with Pb²⁺ showing greater effectiveness than Cu²⁺. Meanwhile, synergistic activation with Cu²⁺ + Pb²⁺ considerably boosted the flotation recovery of hemimorphite. Cu²⁺ and Pb²⁺ were both adsorbed onto the hemimorphite surface, forming an adsorption layer containing Cu or Pb. Following the synergistic activation with Cu²⁺ + Pb²⁺, the activated layer on the hemimorphite surface consisted of Cu and Pb and a larger amount of the active product compared with the surface activated by Cu²⁺ or Pb²⁺ alone. In addition, xanthate adsorption on the hemimorphite surface increased noticeably after synergistic activation with Cu²⁺ + Pb²⁺, suggesting a vigorous reaction between xanthate and the activated minerals. Therefore, synergistic activation with Cu²⁺ + Pb²⁺ effectively increased the content of active products on the hemimorphite surface, thereby enhancing mineral surface reactivity, promoting collector adsorption, and improving surface hydrophobicity.