Since SAR sensors have limited bandwidths

this leads to slow responses to sudden changes （ smearing sharp edges） . Thus

it is difficult to detect edges in SAR images. A new edge detection method is developed to detect edges in SAR images in this paper. There are two steps to accomplish it. First

the local area is segmented into one bright area and one dark area. Second

the boundary of the bright area and the dark area is regarded as the edge

and the edge is identified based on intensity variety. Application of this method to SAR images has shown that the method can effectively detect edges.