Dressing　of　grinding　wheel,　is　necessary　because　of　the　wheel　wear　in　grinding　processes.　Single　diamond　dresser　is　widely　used　in　this　field.　With　the　times　of　dressing　wheels　increasing,　the　diamond　becomes　more　and　more　blunt.　So,　it＇s　a　problem　that　how　to　measure　the　blunt　degree　of　the　diamond　and　when　is　the　best　time　to　replace　it.　In　this　paper,　a　new　try　of　the　identification　of　the　status　of　the　diamond　blunt　is　presented,　which　uses　statistic　process　control(SPC)　and　acoustic　emission　(AE)　technique.　Along　with　the　grinding　operation　going　on,　AE　signals　are　acquired　during　the　course　of　the　diamond　becoming　blunt　by　the　AE　sensor　installed　on　the　support　of　the　diamond　dresser.　Through　the　experiments　it　is　conformed　that　the　AE　signals　are　sensitive　to　the　diamond　being　blunt.　At　the　same　time,　for　deciding　whether　the　diamond　is　blunt　or　not　and　the　blunt　degree　according　to　the　AE　signal,　the　control　chart　and　process　capability(Cp)　index　are　calculated　according　to　the　dimensions　of　the　batch　of　machined　workpieces.　Based　on　the　control　chart　and　Cp　index,　the　time　can　be　estimated　of　the　diamond　being　blunt.　At　the　end　of　the　paper,　a　method　of　the　identification　of　the　status　of　the　diamond　blunt　is　suggested　as　a　future　work.