The　synthesized　WC-8Co　composite　powders　with　the　particle　sizes　of　100,　250　and　400　nm　were　added　to　the　coarse　WC/Co　powders.　The　mixture　was　sintered　at　different　temperatures　in　an　Ar　atmosphere.　The　morphology,　grain　size　and　distribution　of　the　sintered　bulks　were　studied.　The　WC　grain　growth　mechanism　of　the　samples　with　composite　powder　additives　at　different　sintering　stages　was　analyzed.　The　result　shows　that　the　ultra-coarse　cemented　carbide　can　be　prepared　by　WC/Co　mixed　powders　to　which　the　nano　or　submicron　particle　size　composite　powder　additives　are　added.　In　particular,　the　cemented　carbide　with　a　grain　size　of　9.3　mu　m　can　be　prepared　by　using　the　mixed　powder　with　the　nanocomposite　powder　additives　as　raw　materials.　At　the　initial　sintering　stage,　the　addition　of　the　nano　and　submicron　composite　powders　obviously　increases　the　surface　energy　of　the　mixed　powders,　which　is　beneficial　for　promoting　the　growth　of　WC　grains　effectively.　During　the　liquid　sintering,　the　sintered　bulks　with　the　nanocomposite　powder　have　a　larger　dissolution　driving　force,　which　causes　the　small　grains　to　dissolve　and　precipitate　on　the　surrounding　large　grains,　further　increasing　the　grain　size　of　the　sintered　bulks.　In　the　bulks　where　the　submicron　composite　powder　is　added,　the　small　grains　WC　are　concentrated　and　the　dissolution　driving　force　is　small,　and　the　precipitation　mainly　occurs　between　the　surrounding　small　grains,　and　the　dissolved　precipitate　reaches　a　dynamic　equilibrium,　so　that　the　average　grain　size　of　sintered　bulk　grows　slowly.