Three　kinds　of　thermal　spraying　feedstock　powders　with　different　densities　and　sizes　of　WC　particles　were　prepared　using　the　in-situ　synthesized　nanocrystalline　WC-Co　composite　powder　as　raw　material.　The　WC-Co　coatings　were　then　fabricated　by　the　high　velocity　oxy-fuel　thermal　spraying.　The　phase　constitution　of　the　as-sprayed　coatings　and　microstructures　of　the　feedstock　particles　and　the　coatings　were　analyzed.　The　results　show　that　the　coating　prepared　using　the　feedstock　powder　with　a　relatively　higher　density　and　smaller　WC　particle　size　exhibits　simultaneously　low　decarburization　and　high　density,　and　further　enhanced　properties.　The　present　study　suggests　an　effective　method　to　fabricate　the　nanostructured　WC-based　cermet　coatings　with　high　properties.