The　barium-tungsten　cathode　is　widely　used　in　vacuum　electronic　devices.　To　fulfill　the　application　requirements　for　high　current　and　stability,　strontium,　belonging　to　the　same　main　group　as　barium,　is　extensively　employed　as　impregnant　additive　in　cathode　research.　To　elucidate　the　enhancement　mechanism　of　strontium　on　the　performance　of　barium-tungsten　cathode,　we　calculate　the　correlation　between　metal　coverage　and　work　function,　adsorption　energy,　and　electronic　properties.　The　results　demonstrate　that　the　BaxSryO　monolayer　structures　can　achieve　lower　work　functions　on　W(111)　and　W(211)　surfaces　with　metal　coverages　of　0.25-0.333　ML　and　0.5　ML,　respectively.　Hence,　by　adjusting　the　concentration　of　strontium,　the　barium-tungsten　cathode　can　exhibit　outstanding　electron　emission　performance.　In　addition,　Sr　doping　significantly　enhanced　the　adhesion　ability　of　Sr　and　Ba　atoms　on　the　surface,　and　then　improved　the　evaporation　resistance　of　the　active　metal　atoms.　The　electron　density　analysis　shows　that　the　Sr　and　Ba　adatoms　in　low　work　function　structures　exhibit　electron　delocalization,　and　the　electron　excitation　region　is　expanded.　The　calculation　of　the　dipole　moment　indicates　that　the　weak　dipole　repulsion　between　Ba-Sr　atoms　amplifies　the　polarization　effect　of　the　adsorbent,　leading　to　a　reduction　in　the　work　function　of　the　Sr-doped　surface　configuration.