An　important　objective　of　acoustic　emission　(AE)　non-destructive　monitoring　is　to　accurately　identify　approaching　critical　damage　and　to　avoid　premature　failure　by　means　of　the　evolutions　of　AE　parameters.　One　major　drawback　of　most　parameters　such　as　count　and　rise　time　is　that　they　are　strongly　dependent　on　the　threshold　and　other　settings　employed　in　AE　data　acquisition　system.　This　may　hinder　the　correct　reflection　of　original　waveform　generated　from　AE　sources　and　consequently　bring　difficulty　for　the　accurate　identification　of　the　critical　damage　and　early　failure.　In　this　investigation,　a　new　qualitative　AE　parameter　based　on　Shannon＇s　entropy,　i.e.　AE　entropy　is　proposed　for　damage　monitoring.　Since　it　derives　from　the　uncertainty　of　amplitude　distribution　of　each　AE　waveform,　it　is　independent　of　the　threshold　and　other　time-driven　parameters　and　can　characterize　the　original　micro-structural　deformations.　Fatigue　crack　growth　test　on　CrMoV　steel　and　three　point　bending　test　on　a　ductile　material　are　conducted　to　validate　the　feasibility　and　effectiveness　of　the　proposed　parameter.　The　results　show　that　the　new　parameter,　compared　to　AE　amplitude,　is　more　effective　in　discriminating　the　different　damage　stages　and　identifying　the　critical　damage.　(C)　2017　Elsevier　Ltd.　All　rights　reserved.