CNC　grinding　machine　tools　is　the　parent　machine　in　modern　machinery　manufacturing,　our　country＇s　machine　tools　is　a　certain　gap　with　foreign　countries,　therefore,　it　is　very　urgent　to　improve　the　reliability　of　CNC　grinding　machine.　This　article　is　mainly　based　on　data　collected　in　the　factory,　using　Failure　Mode,　Effects　and　Criticality　Analysis　(FMECA),　find　out　the　fault　location　and　the　fault　reasons　of　this　series　of　CNC　grinding　machine,　and　then　identify　the　weaknesses,　provide　the　evidence　for　the　design　and　optimization　of　the　CNC　grinding　machines,　and　propose　appropriate　measures　for　improvement,　to　improve　the　reliability　of　the　series　CNC　grinder.