In　this　work,　WCoB　was　introduced　into　ultra-coarse　cemented　carbides　for　improving　the　oxidation-　and　wearresistance　at　elevated　temperatures.　At　the　initial　oxidation　stage,　WCoB　addition　had　a　slight　effect　on　the　oxidation　rate,　but　enhanced　the　wear　resistance　obviously　by　restraining　the　WC　grains　from　pull-out　and　fracture　as　the　Co　binder　phase　was　preferentially　removed　during　the　wear　process.　At　the　rapid　oxidation　stage,　the　wear　rate　of　the　WCoB-containing　cemented　carbide　was　drastically　decreased　compared　to　that　of　the　straight　WC-Co.　The　wear　of　the　cemented　carbide　was　mainly　caused　by　the　removal　of　the　oxide　layer　and　the　spalling　of　materials　under　the　surface　layer.　WCoB　inhibited　the　oxidation　and　enhanced　the　wear　resistance　of　the　ultra-coarse　cemented　carbides　by　forming　liquid　B2O3　in　the　oxidation　layer　and　sharing　the　stress　with　WC　matrix　before　oxidation.