Pad　conditioning　is　an　important　process　for　the　improvement　of　tool　removal　characteristics　by　controlling　tool　surface　conditions.　This　paper　presents　an　experimental　investigation,　which　attempts　to　reveal　the　influencing　mechanism　of　pad　conditioning　on　the　tool　removal　characteristics　in　bonnet　polishing　process.　By　assistance　of　a　dynamometer,　a　microscope,　a　laser　displacement　sensor,　and　a　pressure　distribution　mapping　system,　multi-comparative　group　experiments　are　carried　out　to　establish　the　correlation　of　pad　conditions,　polishing　forces,　and　tool　removal　characteristic　before　and　after　pad　conditioning.　Through　the　experiments,　three　influencing　mechanisms　are　identified:　(1)　the　asperities　of　the　tool　surface　become　smaller　and　sharper　after　conditioning,　which　indicates　that　the　real　contact　area　between　the　polishing　tool　and　the　workpiece　reduces,　and　the　coefficient　of　friction　(COF)　increases　as　well,　both　leading　to　the　improvement　of　tool　removal　efficiency;　(2)　the　size　of　the　asperity　is　determined　by　the　granularity　of　the　conditioner,　for　which　the　smaller　the　conditioner　granularity　is,　the　smaller　the　asperity　will　be,　leading　to　the　decrease　of　the　real　contact　area;　(3)　the　contour　error　of　bonnet　is　improved　after　pad　conditioning,　so　that　the　periodic　amplitude　of　the　polishing　forces　reduces　and　the　symmetry　of　the　tool　influence　function　(TIF)　becomes　better.　The　influencing　mechanism　identified　in　this　paper　can　be　further　served　as　critical　foundation　for　the　investigation　on　material　removal　determination　through　the　optimization　of　pad　conditioning　process.