Material　processing　using　ultra-short-pulse　laser　is　widely　used　in　the　field　of　micromachining,　especially　for　the　precision　processing　of　hard　and　brittle　materials.　This　paper　reports　a　theoretical　and　experimental　study　of　the　ablation　characteristics　of　a　silicon　wafer　under　micromachining　using　a　femtosecond　laser.　The　ablation　morphology　of　the　silicon　wafer　surface　is　surveyed　by　a　detection　test　with　an　optical　microscope.　First,　according　to　the　relationship　between　the　diameter　of　the　ablation　holes　and　the　incident　laser　power,　the　ablation　threshold　of　the　silicon　wafer　is　found　to　be　0.227 J/cm2.　Second,　the　influence　of　various　laser　parameters　on　the　size　of　the　ablation　microstructure　is　studied　and　the　ablation　morphology　is　analyzed.　Furthermore,　a　mathematical　model　is　proposed　that　can　calculate　the　ablation　depth　per　time　for　a　given　laser　fluence　and　scanning　velocity.　Finally,　a　microchannel　milling　test　is　carried　out　on　the　micromachining　center.　The　effectiveness　and　accuracy　of　the　proposed　models　are　verified　by　comparing　the　estimated　depth　to　the　actual　measured　results.　©　2017　Elsevier　Ltd