It　is　very　challenging　for　3D　printing　based　on　the　selective　laser　melting　(SLM)　technology　to　obtain　cermet　bulk　materials　with　high　density　and　homogeneous　microstructures.　In　this　work,　the　SLM　process　of　the　cermet　powders　was　studied　by　both　simulations　and　experiments　using　the　WC-Co　cemented　carbides　as　an　example.　The　results　indicated　that　the　evolution　of　the　ceramic　and　metallic　phases　in　the　cermet　particle　during　the　heating,　melting　and　solidification　processes　were　all　significantly　inhomogeneous　from　atomic　scale　to　mesoscale　microstructures.　As　a　consequence,　the　microstructural　defects　were　caused　intrinsically　in　the　printed　bulk　material.　The　formation　and　growth　of　the　bonding　necks　between　the　particles　were　mainly　completed　at　the　later　stage　of　laser　heating　and　the　early　stage　of　solidification.　Both　simulations　and　experiments　demonstrated　that　thin　amorphous　layers　formed　at　the　ceramics/metal　interfaces.　This　work　disclosed　the　mechanisms　for　the　evolution　from　the　atomic　scale　to　microstructure　during　the　SLM　printing　of　cermet　powders,　and　discovered　the　origin　of　the　defects　in　the　printed　cermet　bulk　materials.　©　2022　Elsevier　Ltd　and　Techna　Group　S.r.l.