Fe-20Mn-3Cu-1.3C　TWIP　steels　with　the　combination　of　high　strength　and　high　toughness　were　prepared　by　vacuum　melting.　To　address　the　problem　that　micro-porosity　easily　formed　in　the　solidification　structure,　the　effect　of　average　reduction　per　pass　on　micropore　elimination　and　tensile　mechanical　properties　under　the　same　total　hot　rolling　reduction　was　studied.　The　results　show　that　when　the　average　reduction　per　pass　raises　from　35.96%　to　48.75%,　the　section　density　of　micropore　in　the　alloys　remarkably　decreases　and　the　average　grain　size　decreases　as　well,　and　the　yield　strength,　tensile　strength　and　strength-plasticity　product　are　also　greatly　enhanced.　When　the　average　reduction　per　pass　is　48.75%,　the　yield　strength,　tensile　strength　and　elongation　percentage　is　536.70　MPa,　1161.49　MPa　and　95.60%,　respectively.　And　the　strength-plasticity　product　is　111038.4　MPa·%,　which　increases　by　47.70%　compared　with　the　data　obtained　from　the　average　reduction　per　pass　at　35.96%　and　the　result　is　the　highest　value　of　performance　data　of　TWIP　steels　so　far.　Eliminating　micropore　by　increasing　the　average　reduction　per　pass　is　the　key　to　improve　mechanical　properties　of　the　TWIP　alloy.