The　joint　of　the　toolholder-spindle　is　the　most　weakness　structure　in　the　system　of　toolholder-spindle.　It　affects　the　manufacturing　efficiency　and　the　surface　quality　of　work　piece.　It　is　important　to　identify　the　dynamic　contact　parameters　for　evaluating　the　connectivity　of　the　toolholder-spindle　system.　The　article　introduces　an　approach　to　identify　the　dynamic　contact　parameters　of　toolholder-spindle　joint　base　on　frequency　response　function　(FRF).　Using　the　BT40　todholder-spindle　system,　we　can　get　the　dynamic　contact　parameters　curve　of　toolholder-spindle　by　the　previous　approach.　The　translational　and　rotational　contact　parameters　can　be　obtained　by　sensitivity　analysis.　By　comparing　the　simulation　results　with　those　of　experimentation,　it　can　prove　the　validity　of　identified　dynamic　contact　parameters.　The　research　results　can　provide　a　theoretical　basis　for　the　optimization　of　toolholder.