Based　on　a　cutting　dynamics　model,　a　new　digital　machining　process　model　that　integrates　workpiece　quality　and　machining　condition　information　is　proposed,　and　the　mapping　relationship　between　machine　tool　structural　dynamics　and　product　quality　information　(e.g.,　dimension　error,　surface　shape)　is　analyzed　in　detail.　On　the　basis　of　the　digital　machining　process　model,　the　condition　monitoring　and　fault　diagnosis　method　of　the　machining　process　is　investigated,　and　an　implementation　flowchart　of　the　method　is　proposed　with　explanations　of　critical　techniques.　Finally,　the　proposed　model　is　applied　to　the　condition　monitoring　and　fault　diagnosis　of　the　machining　process　of　a　CNC　end　milling　machine.　The　damage　of　its　spindle　bearing　is　detected　successfully,　which　provides　the　proof　for　the　root　cause　identification　of　machining　error　in　the　digital　machining　process.