Three　representative　sulfide　ore　samples　were　collected　from　typical　metal　mines,　and　their　corresponding　pre-oxidized　products　were　obtained　under　nature　environment.　The　thermal　behaviors　of　each　sample　at　heating　rates　of　5,　10,　15　and　20　C/min　in　air　flow　from　ambient　temperature　to　800　C　were　studied　by　simultaneous　thermal　analysis　and　the　TG/DSC　curves　before　and　after　the　pre-oxidation　were　compared.　By　the　peak　temperature　of　DTG　curves,　the　whole　reaction　process　for　each　sample　was　divided　into　different　stages,　and　the　apparent　activation　energies　were　calculated　by　the　Ozawa-Flynn-Wall　method.　The　results　show　that　the　reaction　process　of　each　sample　after　pre-oxidation　is　more　complex,　with　quicker　reaction　rates,　fewer　heat　production　quantities,　and　higher　or　lower　ignition-points.　The　apparent　activation　energies　decrease　from　364.017-474.228　kJ/mol　to　244.523-333.161　kJ/mol.　Therefore,　sulfide　ores　are　more　susceptible　to　spontaneous　combustion　after　the　pre-oxidation.　©　2014　Central　South　University　Press　and　Springer-Verlag　Berlin　Heidelberg.