The　sintering　densification　behavior　and　microstructural　evolvement　of　W-Cu-Ni　alloys　(90　wt%　W,　5　wt%　Cu,　5　wt%　Ni)　were　investigated　via　selective　laser　sintering　(SLS).　Through　the　analysis　of　the　surface　morphology　and　microstructure　obtained　by　different　laser　sintering　parameters,　revealing　that　the　sintering　mechanism　evolves　from　solid　state　sintering　to　liquid　phase　sintering　depends　on　the　laser　input　energy.　The　sintered　density　initially　increases　with　the　laser　input　energy　then　decreases;　the　poring　and　balling　phenomenon　cannot　be　eliminated　drastically.　The　SLS　of　W-5Cu-5Ni　(wt%)　alloys　is　a　complete　process　of　molten　liquid　phase　spreading　and　solidifying,　which　is　determined　by　the　intrinsic　properties　of　W/Cu　and　the　laser　sintering　parameters.　Setting　a　moderate　temperature　for　the　molten　pool　would　restrain　the　phenomenon　of　balling　and　poring,　so　as　to　achieve　a　sintered　sample　which　is　nearly　densified.　Combined　with　composition　and　phase　analysis,　Ni-Cu　is　acting　as　the　binder　phase,　adding　Ni　additive　promotes　partially　dissolution　of　W,　meanwhile　most　nonmelting　W　is　acting　as　structural　phase.