Wavelet denoising of Donoho and Johnstone in multiresolution approximation has been evolved to become very powerful tools for digital signal processing.But the determining of the parameter

jo

the low-resolution cutoff

is difficult in general case.It needs some regularities of the source signal.Which

jo

is the best for a given unknown signal and a noise power σ?In this paper

we construct a statistic for looking for the best jo adaptively.We analyze the properties of the statistic and give many simulation results.This adaptive method makes the scope of application of the wavelet denoising more widely.