It　is　very　crucial　to　accurately　identify　the　parameters　of　contact　dynamics　in　predicting　the　chatter　stability　of　spindle　tool　holder　assemblies　in　machining　centers.　Fast　and　accurate　identification　of　contact　dynamics　in　spindle　tool　holder　assembly　has　become　an　important　issue　in　the　recent　years.　In　this　paper,　the　receptance　coupling　substructure　approach　is　employed　for　identification　the　stiffness　and　damping　of　the　interface　in　a　simple　manner,　in　which　the　frequency　response　function　of　the　tool　holder　is　derived　from　the　Timoshenko　beam　finite　elements　model.　A　BT　50　type　tool　holder　is　adopted　as　an　application　example　of　the　method.　Although　this　study　focuses　on　the　contact　dynamics　at　the　spindle　tool　holder　interfaces　of　the　assembly,　the　approach　might　be　used　for　identifying　the　dynamical　parameters　of　other　critical　interface.