We　studied　the　structural　and　elemental　evolutions　during　the　femtosecond　laser　percussion　drilling　of　high-aspect-ratio　diamond　microholes.　Microholes　225-mu　m-deep　having　an　aspect　ratio　of　15　were　drilled　with　an　exposure　time　of　100　s　and　a　laser　power　of　60　mW.　It　is　found　that　when　the　specimen　was　machined　by　femtosecond　laser　at　low　power　and　short　exposure　time,　the　laser-affected　zone　(LAZ)　may　be　still　solid　in　the　interior　rather　being　void,　even　it　reached　the　bottom　of　the　diamond.　A　clear　crack　appeared　between　the　solid　portion　and　pristine　diamond.　Elemental　analysis　revealed　that　oxygen　was　incorporated　into　the　solid　portion　of　the　LAZs,　and　its　atomic　percentage　reached　6.5%　for　a　laser　power　of　10　mW　at　initial　position　and　decreased　as　the　depth　increased　in　the　solid　portion.　The　wall　of　the　void　contained　nearly　no　oxygen.　Furthermore,　nanoripples　were　observed　on　the　sidewall　surface　of　the　hole.　(C)　2022　Society　of　Photo-Optical　Instrumentation　Engineers　(SPIE)