The　high-entropy　alloys　(HEAs)　exhibit　outstanding　high-temperature　properties　and　promise　in　a　wide　range　of　applications,　such　as　aviation,　nuclear　energy　and　other　fields.　However,　the　problems　of　formability　and　defect　control　limit　the　successful　realization　of　HEAs.　Herein,　we　newly　developed　NbMoTaTi0.5Ni0.5　HEA　which　renders　a　high　room-temperature　compressive　strength　of　2297　MPa　and　high-temperature　(1000　°C)　compressive　strength　of　651　MPa.　Meanwhile　we　present　that　the　addition　of　both　Ni　and　Ti　can　suppress　the　crack　formation　and　enhance　the　formability　of　NbMoTa　HEA,　prepared　by　selective　laser　melting　(SLM),　without　compromising　the　mechanical　performance.　Actually,　the　fracture　is　suppressed　by　the　transformation　of　microcracks　due　to　grain　boundaries　with　low　stacking　fault　energy　(SFE)　which　can　greatly　improve　the　formability　of　HEAs　while　ensuring　its　high-temperature　performance.　The　current　study　shall　serve　as　a　guideline　for　the　development　of　refractory　high-entropy　alloys　via　additive　manufacturing,　such　as　selective　laser　melting.　©　2021　The　Authors