The　interactions　between　fine　and　coarse　hematite　particles　were　investigated,　and　their　effects　on　the　flotation　of　the　hematite　using　sodium　oleate　as　a　collector　were　studied　through　micro-flotation　tests,　supplemented　by　optical　microscopic　analysis,　extended　Derjaguin-Landau-Verwey-Overbeek　(EDLVO)　theoretical　analysis,　and　focused　beam　reflectance　measurement　(FBRM)　particle/aggregate　size　analysis.　The　micro-flotation　results　show　that　the　recovery　of　hematite　from　fine-coarse　hematite　mixtures　did　not　decrease　monotonously　with　increasing　the　fine　hematite　mass　ratio.　The　highest　recovery　was　obtained　when　the　fine　and　coarse　hematite　were　approximately　equal　in　mass　ratio,　indicating　that　the　interactions　between　fine　and　coarse　hematite　particles　could　promote　the　overall　flotation　recovery.　The　results　of　optical　microscopy　analysis,　EDLVO　calculation,　and　FBRM　measurements　showed　that　the　interaction　energies　and　aggregation　tendencies　between　fine　and　coarse　hematite　particles　were　stronger　than　that　among　the　fine　hematite　particles,　and　the　aggregation　would　weaken　when　the　coarse　and　fine　fractions　were　mixed　in　extreme　mass　ratios,　which　explained　the　observed　effects　of　different　mixing　ratios　of　fine　and　coarse　hematite　particles　on　their　flotation.