The　de-noising　effects　of　wavelet　transform,　soft　threshold,　hard　threshold　and　the　new　threshold　wavelet　packet　were　compared　by　simulation　experiments　in　the　paper.　It　is　concluded　that　the　wavelet　packet　has　a　good　time　and　frequency　domain　localization　properties　and　multi-resolution　analysis,　and　the　new　threshold　method　can　de-noise　noisy　spectrum　effectively,　overcome　the　constant　bias　and　discontinuity　defects　of　soft　and　hard　threshold　function.　©　2011　Intl　Journal　of　Adv　Mechatr.