High-aspect-ratio　microholes,　the　fundamental　building　blocks　for　microfluidics,　optical　waveguides,　and　other　devices,　find　wide　applications　in　aerospace,　biomedical,　and　photonics　fields.　Yttrium　aluminum　garnet　(YAG)　crystals　are　commonly　used　in　optical　devices　due　to　their　low　stress,　hardness,　and　excellent　chemical　stability.　Therefore,　finding　efficient　fabrication　methods　to　produce　high-quality　microholes　within　YAG　crystals　is　crucial.　The　Bessel　beam,　characterized　by　a　uniform　energy　distribution　along　its　axis　and　an　ultra-long　depth　of　focus,　is　highly　suitable　for　creating　high-aspect-ratio　structures.　In　this　study,　an　axicon　lens　was　used　to　shape　the　spatial　profile　of　a　femtosecond　laser　into　a　Bessel　beam.　Experimental　verification　showed　a　significant　improvement　in　the　high　aspect　ratio　of　the　microholes　produced　in　YAG　crystals　using　the　femtosecond　Bessel　beam.　This　study　investigated　the　effects　of　the　power　and　defocus　parameters　of　single-pulse　Bessel　beams　on　microhole　morphology　and　size,　and　microhole　units　with　a　maximum　aspect　ratio　of　more　than　384:1　were　obtained.　Based　on　these　findings,　single-pulse　femtosecond　Bessel　processing　parameters　were　optimized,　and　an　array　of　181　x　181　microholes　in　a　400　mu　m　thick　YAG　crystal　was　created　in　approximately　13.5　min.　The　microhole　array　had　a　periodicity　of　5　mu　m　and　a　unit　aspect　ratio　of　315:1,　with　near-circular　top　and　subface　apertures　and　high　repeatability.