As a kind of imaging radars, synthetic aperture radar (SAR) improves its resolution by means of moving and emitting pulse repetitiously. The issues about target detection of SAR are often a 憄ost-process?of the SAR imaging. A method for coastline extraction in the state of non-imaging based on analyzing the typical algorithms of SAR imaging and target detection is presented in this paper. Experimental results indicate the validity of the algorithm for coastline extraction. The algorithms are simple, able to recurrent, and easy for real-time processing and hardware implementation.