Ba　dispenser　cathode　is　the　widely　applied　thermionic　cathode　at　present.　In　order　to　improve　the　emission　property　of　the　cathode　to　meet　the　requirement　for　the　high　power　vacuum　electron　devices,　Ir　was　added　in　the　dispenser　cathode.　It　is　found　that　the　emission　property　could　be　improved　after　adding　Ir　since　it　enhances　charge　transfer　from　Ba　to　O　and　further　stabilizes　the　interface　configuration　of　Ba-O-W-Ir.　It　is　also　found　that　the　composition　of　the　surface　layer　change　with　the　activation　and　operation　time.　IrW　in　the　cathode　would　benefit　for　the　improvement　of　the　cathode　performance.　©　2023　IEEE.