This　paper　proposes　an　improved　beta-order　Weighted　Euclidean　Distortion　Measure　(I-beta-WEDM)　spectral　estimator　for　speech　enhancement.　The　new　beta-order　WEDM　gain　function　is　introduced,　in　which　a　novel　method　of　computing　order　beta　is　proposed.　In　this　method,　the　input　noisy　signal　is　divided　into　several　critical　bands　in　the　human　auditory　model.　The　value　of　order　beta　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　beta　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　beta　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.