The　cathode　in　the　magnetron　should　have　good　secondary　emission　property　and　a　certain　thermionic　property.　In　this　article,　ZrH2　was　added　as　an　activator　to　obtain　rare　earth-doped　tungsten　matrix　impregnated　cathode　to　improve　the　emission　property.　Cathodes　with　ZrH2　(Y15-411-Zr　cathode)　or　without　ZrH2　(Y15-411　cathode)　were　prepared　by　a　spray　drying　method　combined　with　high-temperature　sintering　in　dry　hydrogen　atmosphere.　The　emission　properties　and　emission　mechanism　have　been　studied.　The　results　showed　that　thermionic　emission　performance　and　secondary　emission　performance　of　Y15-411-Zr　cathode　are　3.4　times　and　1.2　times　higher　than　those　of　Y15-411　cathode,　respectively.　With　the　addition　of　ZrH2,　yttrium　was　produced　during　activating　process,　which　contributed　to　the　better　emission　properties　of　Y15-411-Zr　cathode.　Furthermore,　the　work　function　of　barium　and　oxygen　adsorbed　on　yttrium　oxide　and　yttrium　surface　was　calculated　using　the　first　principle.　The　results　showed　that　the　lowest　work　function　of　Ba-O　absorbed　on　Y2O3　and　Y　is　1.9　and　1.6　eV,　respectively.