Abstract: A novel filter called Linear Mixed Filter（LMF） is proposed in this paper，which is suitable for digital images corrupted with mixed noises（impulse noise and Gaussian noise）.It has an automatic adjustment mechanism when the noise change.Comparing with some similar filters，it needs fewer time to restore an image，with simple and unified control parameter formulas（not a range of them） and the peak signal to noise ratio for a number of denoised images are increased while the mean square errors are reduced by experiments.