The　ultrafine　WC-Co　composite.　powder　was　synthesized　by　in　situ　reactions　of　metal　oxides　and　carbon.　The　thermal　spraying　feedstock　was　prepared　by　granulation　using　the　as-synthesized　composite　powder.　The　influence　of　carbon　addition　in　the　starting　powders　on　the　phase　constitution　and　chemical　composition　of　the　prepared　composite　powder　and　spraying　feedstock　as　well　as　on　the　microstructure　and　mechanical　properties　of　the　sprayed　cermet　coating　was　investigated.　By　adjusting　the　carbon　addition　in　the　initial　stage,　the　pure　phase　constitution　can　be　obtained　in　the　prepared　spraying　feedstock.　In　the　subsequent　thermal　spraying,　the　decarburization　can　be　inhibited　by　the　free　carbon　existing　in　the　feedstock　powder.　With　an　appropriate　carbon　addition,　the　prepared　ultrafine-structured　coating　has　the　best　combination　of　hardness　and　toughness　and　thus　the　coating　exhibits　the　highest　wear　resistance.　The　present　work　indicates　the　significant　role　of　carbon　control　during　the　preparation　processes　of　WC-Co　coatings.　(c)　2013　Elsevier　B.V.　All　rights　reserved.