Using　single　point　diamond　knife　and　quadratic　general　regression　rotary　unitized　design　to　do　cutting　experiments　of　special　crystals　(KDP　crystal),　and　using　acoustic　emission　technique　to　collect　signal　of　KDP　crystal　with　different　surface　waviness,　measure　and　analyze　the　test　results.　By　frequency　domain　and　time　domain　analys　is,　it　can　be　obtained　that150-200KHz　can　be　a　characteristic　band　to　monitor　KDP　crystal　surface　waviness　online　and　mean-square　value　can　be　used　an　important　time　Domain　feature　to　monitor　the　process　of　KDP　crystal　surface　wavinessstatus