A switched adaptive filtering algorithm is proposed for removing the high density salt-pepper noise.At first,the algorithm performs noise detection based on the window′s signal pixels and the probable noise pixel distribution,then the noise density is calculated.The filtering method to average adjacent signal pixels′ value is applied to low noise density image area.The filtering method of weighted iteration is applied to high noise density（30%）image area.Experimental results show that this algorithm can suppress noise effectively.Especially for high noise density（90%） cases,the PSNR is about 10 dB higher than other methods.