WC　powders　with　different　particle　sizes　and　ultrafine　Co　powders　were　mixed　to　form　the　initial　powders.　Afterwards　ultrafine　WC-Co　cermet　bulks　were　prepared　by　direct　SPS　and　a　new　method　combining　vacuum　pretreatment　with　SPS.　Results　show　that　the　samples　prepared　by　pretreatment　and　SPS　have　a　little　lower　hardness　but　higher　fracture　toughness　and　much　higher　tensile　strength　than　those　by　direct　SPS.　The　analyses　of　microstructures　and　properties　indicate　that　the　vacuum　pretreatment　has　important　effect　on　the　WC-Co　cermets　by　SPS.　It　can　release　the　adsorbed　gas,　cancel　the　＂Co　lake＂　and　obtain　completely　densified　bulks　without　significant　grain　growth.