This paper presents an iterative filtering method on the de-noising of Synthetic Aperture Radar (SAR) image based on block matching. Firstly, it makes use of the similarity among the image blocks to conduct block matching and to construct a three-dimensional matrix of the similar image block. And then, it performs iteration filtering to remove speckle noise in transform domain among similar image blocks, so that we can obtain the basic estimation denoised image after reconstruction by weighted average. Finally, it performs block matching on the basic estimate denoised image, and filters in the similar image blocks and among the similar image blocks to get the final denoised image by 3-D experience filter. Experiments show that the proposed method can effectively suppress speckle noise of SAR image, while preserving better the edge and texture information.