Abstract: In order to filter the Gaussian noise in digital image,combining the Mathematical morphology and Wavelet domain enhancement,a new filter algorithm is put forward.Firstly,the noise image is conducted two-dimensional wavelet decomposition,obtaining high-frequency and low-frequency sub image.Then keep the low-frequency sub image unchanged,according to the characteristics of the Gaussian noise distribution in each high-frequency sub image,the multi-angles,multi-structure mathematical morphology filters are designed to filter out the Gaussian noise,then the wavelet coefficient are reconstructed.Finally,the image after mathematical morphology filtering are conducted two layer wavelet decomposition,a new wavelet domain enhancement function is designed so as to contract the different amplitude wavelet coefficients in different degree,then the wavelet coefficient are reconstructed.The adaptive average filter and mathematical morphology and the new filter algorithm in this paper are applied to denoising the Gaussian noise in digital image respectively,the experiment results show that the new filter algorithm in this paper is better than the others.