Thermodynamic　calculations　were　carried　out　on　typical　tungsten　cathode　materials　using　Factsage　software　within　a　temperature　range　of　1000-3400　degrees　C.　The　relationship　between　the　phase　stability　and　electron　emission　performance　of　the　cathode　in　a　vacuum　environment　and　under　a　protective　atmosphere　was　investigated.　The　thermodynamic　stability　of　tungsten　cathodes　doped　with　different　proportions　of　carbides　and　oxides　was　calculated.　It　was　found　that　when　the　doped　phase　(ThO2,　La2O3,　Y2O3,　Lu2O3,　Er2O3,　Gd2O3,　TiO2,　ZrO2,　HfO2,　ThC2,　LaC2,　YC2,　TiC,　ZrC,　and　HfC)　in　the　cathode　starts　to　be　consumed,　the　electron　emission　performance　of　the　cathode　will　decline.　Therefore,　the　high-temperature　stability　of　the　doped　phase　carbides　and　oxides　also　affects　the　operating　temperature　of　the　cathode.　To　verify　these　results,　this　study　tested　the　electron　emission　performance　of　W-La2O3,　W-ThO2,　W-ZrO2,　W-ZrC,　and　W-HfC,　plotting　their　volt-ampere　characteristic　curves.　The　results　indicated　that　the　W-La2O3　cathode　exhibits　the　best　emission　performance　at　low　temperatures,　while　the　W-ThO2,　W-ZrO2,　W-ZrC,　and　W-HfC　cathodes　showed　better　emission　performance　at　high　temperatures.　The　experimental　results　are　in　good　agreement　with　the　simulation　results.　The　thermal　stability　of　the　doped　phase　is　closely　related　to　the　high-temperature　thermal　stability　of　the　cathode.