The　single-crystal　lanthanum　hexaboride　(LaB6)　field　emission　array　with　uniformly　hill-shaped　emitter　morphology　was　quickly　fabricated　(30　min)　using　an　ultraviolet　femtosecond　laser.　The　height　of　each　hill-shaped　emitter　is　6　mu　m,　and　the　curvature　radius　is　100　nm.　The　phase　and　composition　analysis　shows　that　the　ultraviolet　femtosecond　laser　has　minimal　thermal　damage　to　the　single　crystal　LaB6　array.　The　field　emission　characteristics　indicate　that　the　processed　array　has　a　starting　electric　field　of　2.1　V/mu　m,　and　the　field　emission　current　density　reaches　0.76　A/cm(2).　The　first-principles　calculation　shows　that　the　work　function　of　single-crystal　LaB6　is　significantly　reduced　to　0.45　eV　under　a　strong　electric　field　(0.1　V/angstrom),　which　making　free　electrons　easier　to　form　electron　emission.　This　calculation　results　provide　a　theoretical　basis　for　our　experiment.　These　results　provide　a　potential　path　for　the　rapid　fabrication　of　single-crystal　LaB6　arrays　with　excellent　field　emission　characteristics.