La-Y-Ce-W　cathode　was　prepared　by　powder　metallurgy.　XRD,　OM,　SEM　and　EDS　were　applied　to　analyze　the　microstructure　of　the　material.　La,　Ce　and　Y　concentrate　on　the　tungstate　particles　and　exist　as　Rare　Earth　(RE)　tungstate.　The　average　diameter　of　the　particles　is　about　30　mu　m.　The　electron　emission　properties　were　measured　with　self-designed　electron　emitter　surveyor.　Its　effective　work　function　was　2.76eV　at　1300　degrees　C.　The　precipitation　efficiency　of　an　electrostatic　precipitator　(ESP)　installed　with　the　cathode　was　investigated　in　a　certain　flue　gas　condition.　It　was　found　that　it　can　trap　over　95%　dust　particles　with　diameter　bigger　than　1　mu　m.　As　to　dust　particles　with　diameter　smaller　than　0.1　mu　m,　the　efficiency　is　lower　than　85%.　Increasing　collection　voltages　showed　greater　positive　effects　on　the　precipitation　efficiency　of　smaller　particles　than　that　of　larger　particles.