Selective　laser　melting　(SLM)　of　pure　molybdenum　encounters　all　the　difficulties　of　SLM　metals　due　to　its　intrinsic　properties　(high　melting　point,　high　ductile-to-brittle　transition　temperature　and　high　surface　tension).　In　this　work,　we　studied　the　influence　of　key　factors　such　as　powder　morphology　and　processing　parameters　on　SLM　fabricated　pure　molybdenum.　Pure　molybdenum　with　a　relative　density　of　99.1%　was　fabricated　by　SLM　using　optimized　processing　parameters.　The　formation　mechanisms　for　densification　behavior　and　crack　growth　behaviors　are　systematically　analyzed.　Electron　backscattered　diffraction　analysis　indicates　that　the　interlocking　grain　boundary　structure　and　stretch　columnar　grains　can　increase　bonding　force　and　inhibit　crack　growth.　The　balling　and　cracking　can　be　reduced　by　adding　support　structure　and　suppressing　oxygen　content.　The　hardness　of　SLM-fabricated　molybdenum　exceeding　260　HV,　which　is　30-37%　higher　than　Mo　prepared　by　conventional　manufacturing　methods,　mainly　attributed　to　the　fine　grains　and　dislocation　strengthening　in　the　SLM　process.　The　bending　strength　of　SLM-ed　Mo　reached　280　+/-　52　Mpa.　The　fracture　mode　of　SLM　Mo　was　intergranular.　This　study　provides　a　new　route　for　the　fabrication　of　refractory　metals　with　a　complex　structure.