In　this　study,　the　effects　of　copper　ions　(Cu2+)　on　the　sulfidization　(Na2S)　flotation　of　malachite　was　investigated　using　micro-flotation　experiments,　zeta-potential　measurements,　X-ray　photoelectron　spectroscopy　(XPS)　analysis,　adsorption　experiments,　and　Materials　Studio　simulation.　The　results　indicated　that　the　flotation　recovery　of　malachite　decreased　after　the　pretreatment　of　the　mineral　particles　with　Cu2+　ions　prior　to　the　addition　of　Na2S.　The　results　for　zeta-potential　measurements　and　XPS　analysis　revealed　that　less　sulfide　ion　species　in　the　pulp　solution　transferred　onto　the　mineral　surface,　the　sulfidization　of　malachite　surface　weakened.　The　adsorption　amount　of　collector　on　the　mineral　surface　decreased,　and　this　finding　was　confirmed　by　the　results　of　the　zeta-potential　and　adsorption　experiments.　Materials　Studio　simulation　revealed　that　the　adsorption　energy　of　HS-ions　and　C4H9OCSS　-　ions　on　malachite　surface　increased　after　the　adding　of　Cu2+　ion.　The　competitive　adsorption　made　Cu2+　ions　depress　sulfidization　flotation　of　malachite,　the　dissolution　of　mineral　surface　affected　the　adsorption　of　reagents　on　it,　and　decreased　the　floatability　of　malachite.