Almost　fully　dense　ALCrFeNiV　HEA　consisting　of　face-centred-cubic　(FCC)　solid　solution　and　L1(2)　nano　phase　was　prepared　from　gas-atomized　alloy　powder　with　optimized　selective　laser　melting　(SLM)　processing　parameters.　Microstructure　characterization　reveals　the　presence　of　hierarchical　structures　including　columnar　grains,　sub-grains,　L1(2)　nano　phase　and　dislocations　in　SLMed　HEA.　Unique　columnar　grains　ranging　from　several　tens　of　microns　up　to　200　mu　m　grow　along　the　direction　of　the　temperature　gradient.　High　cooling　speed　and　non-equilibrium　solidification　during　SLM　process　induced　the　formation　of　sub-grains　in　every　columnar　grain,　accompanied　with　the　heterogeneous　distribution　of　dislocations　and　L1(2)　nano　phase.　The　SLMed　AlCrFeNiV　HEA　exhibited　an　outstanding　combination　of　high　strength　(ultimate　tensile　strength　similar　to　1057.47　MPa)　and　excellent　ductility　(plastic　strain　similar　to　30.3%).　The　characteristic　hierarchically　heterogeneous　structure　contributes　to　the　increase　of　strength　without　losing　ductility.　The　sub-grains　contribute　significantly　to　the　enhanced　strength　through　dislocation　hardening.　The　excellent　ductility　is　correlated　with　the　progressive　work-hardening　mechanism　regulated　by　the　heterogeneous　distribution　dislocation　and　L1(2　)nano　phase　within　sub-grains.　(C)　2019　Elsevier　B.V.　All　rights　reserved.