3-Ethyl-4-pyridylamidoxime　(EPA)　and　3-methyl-5-tert-butyl-4-pyridylamidoxime　(MBPA)　were　introduced　as　the　collectors　in　the　flotation　and　enrichment　of　malachite　from　calcite　and　quartz.　Compared　with　MBPA　and　the　traditional　collector　benzohydroxamic　acid　(BHA),　EPA　exhibited　a　better　flotation　performance.　Its　collecting　ability　to　malachite　was　stronger　than　BHA,　and　its　selectivity　toward　calcite　and　quartz　was　better　than　MBPA.　In　the　absence　of　Pb2　+　ions,　2.0　x　10(-4)　mol/L　EPA　at　pH　8.0　could　recover　about　86　%　malachite,　20　%　calcite　and　22　%　quartz.　Under　the　same　conditions,　BHA　floated　out　around　58　%　malachite,　27　%　calcite　and　10　%　quartz.　The　contact　angle　and　SEM　proved　that　EPA　could　enhance　the　surface　hydrophobicity　of　malachite　via　corrosion　to　produce　more　active　sites　for　its　heavy　adsorption.　FTIR　and　XPS　revealed　that　EPA　would　chelate　with　the　surface　Cu　atom　to　form　-O-Cu　and　-N-Cu　bonds.　EPA　owned　stronger　electron-donating　ability　and　worse　electron-accepting　ability　than　BHA,　which　brought　a　stronger　chemical　reactivity.　Moreover,　its　isomer　could　further　enhance　the　adsorption　ability　onto　malachite.　The　novel　amidoxime　collector　EPA　was　able　to　efficiently　lead-free　enrich　malachite　and　enhance　the　industrial　capacity　to　treat　copper　oxide　ores.