The　interface　of　the　spindle-tool　holder　is　the　most　weakness　structure　in　the　system　of　spindle-tool　holder.　It　affects　the　manufacturing　efficiency　and　the　surface　quality　of　work　piece.　It　is　important　to　identify　the　dynamical　contact　parameters　to　evaluate　the　connectivity　of　the　spindle-tool　holder　system.　The　paper　advises　a　method　to　identify　the　dynamical　contact　parameters　for　spindle-tool　holder　interface　based　on　frequency　response　functions.　The　least　squares　solution　to　solve　model　is　used.　With　the　spindle-tool　holder　system　of　BT40　as　an　example,　it　can　get　the　frequency　response　functions　through　Ansys　and　identify　the　dynamical　contact　parameters　for　the　spindle-tool　holder　interface.　It　can　get　the　different　stiffness　on　the　different　drawbar　force　and　different　position　of　the　spindle-tool　holder　interface　and　the　validation　shows　that　identification　of　the　dynamical　contact　parameters　for　spindle-tool　holder　interface　with　the　proposed　method　is　right.　The　research　can　provide　a　theoretical　basis　for　the　optimization　of　tool　holder.