Hot　isostatic　pressing　(HIP)　is　usually　applied　to　reduce　the　defects　including　cracks　and　pores　in　the　materials　prepared　by　laser　powder　bed　fusion　(LPBF).　In　the　present　research,　in　order　to　improve　the　relative　density　and　mechanical　property,　HIP　was　employed　on　the　LPBF-processed　Al-Cr-Fe-Ni-V　high-entropy　alloy　(HEA)　with　microcracks　and　pores.　The　microstructure　evolution　and　property　improvement　induced　by　HIP　were　investigated.　In　the　LPBF-processed　HEA,　the　microcracks　were　caused　by　residual　stress　and　element　segregation,　and　these　microcracks　as　well　as　the　pores　reduced　significantly　after　HIP　treatments.　Remarkably,　HIP　temperature　has　a　more　critical　effect　on　the　microcrack　closure　than　the　holding　time,　thus,　microcracks　and　pores　still　existed　after　HIP-1　treatment　(1273　K,　8　h),　while　HIP-2　treatment　(1473　K,　4　h)　could　close　the　microcracks　significantly.　The　crack　closure　was　attributed　to　the　interfacial　diffusion　of　the　alloying　element　under　high　temperature　accompanied　by　high　pressure,　and　the　degree　of　element　diffusion　at　both　interfaces　of　the　cracks　determined　the　bonding　strength　after　crack　closure.　Higher　temperatures　at　high　pressure　induced　more　adequate　element　diffusion　and　higher　bonding　strength.　The　above　high　temperature　and　high　pressure　also　induced　the　growth　of　the　L12　phase　and　the　precipitation　of　the　B2　phase　in　HEA.　Consequently,　the　tensile　strength　and　elongation　of　the　LPBF-processed　HEA　after　HIP-2　treatment　were　simultaneously　enhanced　(80.7%　and　222.5%　higher　than　that　of　LPBF-processed　HEA,　respectively).　This　could　be　attributed　to　the　combined　effect　of　microcrack/pore　closure　and　precipitation　strengthening.　The　strengthening　effect　of　the　B2　phase　and　L12　phase　accounted　for　53%　(dislocation　by-pass　mechanism)　and　47%　(dislocation　shearing　mechanism)　of　the　total　precipitation　strengthening,　respectively.　©　2023