The　corrosion　of　magnesia－chrome　refractory　by　molten　CaO-SiO2－Aｌ203－FetO-MgO　slags　has　been　examined　at 1500℃　in　argon　atmosphere．The　results　obtained　are　summarized　as　follows： 　1）Main　corrosion　modes　of magnesia－chrome　refractory　by　molten　CaO－SiO2－Al2O3－FetO－MgO　slags　in static　condition　are　the　local　corrosion　at　the　slag　surface　and　the　pit　like　corrosion　at　the bottom　surface　of　the refractory　specimen　in　the　bulk　slag　phase　and　also　in　the　upper　part　of　local　corrosion　zone、 　2）　Local　corrosion　rate　and　bulk　corrosion　rate　increase　with　increasing　in　T．Fe　concentration　and decreasing　in　MgO，Al2O3 concentrations　of　slag　and　Cr2O3 content　of　the　refractory　specimen． 　3）　Local　corrosion　and　pit　like　corrosion　are　mainly　caused　by　Marangoni　convection　induced　by　the　surface tension　gradient　along　the　surface　of　slag　film　which　forms　on　the　refractory　specimen　of　the　local　corrosion　zone or　the　bubble　surface　near　the　wall　of　refractory　specimen． 　4）　The　surface　tension　gradient　is　caused　by　the　concentration　gradient　of　MgO，Cr2O3 and　Al2O3 on　the　slag film　surface　due　to　the　dissolution　of　MgO，Cr2O3 from　the　refractory　specimen　and　Al2O3 from　the　alumina crucible，respectively．

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