This　paper　proposes　an　improved　β-order　Weighted　Euclidean　Distortion　Measure　(I-β-WEDM)　spectral　estimator　for　speech　enhancement.　The　new　β-order　WEDM　gain　function　is　introduced,　in　which　a　novel　method　of　computing　order　β　is　proposed.　In　this　method,　the　input　noisy　signal　is　divided　into　several　critical　bands　in　the　human　auditory　model.　The　value　of　order　β　is　updated　adaptively　according　to　the　signal-to-noise　ratios　(SNR)　which　are　computed　in　different　critical　bands.　The　performance　of　the　proposed　estimator　with　different　values　of　β　has　been　evaluated　by　ITU-T　G.160　under　the　white　noise　and　the　non-stationary　noise,　respectively.　The　experimental　results　show　that,　comparing　with　the　reference　algorithms,　the　proposed　algorithm　with　adaptive　β　could　provide　large　amount　of　noise　reduction,　and　has　a　little　impact　on　the　level　of　speech　signal.　The　quality　of　enhanced　speech　is　improved　at　the　same　time.　©　2011　IEEE.