Regularization technique could enhance SAR(Synthetic Aperture Radar) image by imposing prior information. In this paper, firstly,the prior information in existence is analyzed, a feature-enhanced SAR image formation technique based on regularization in amplitude domain is proposed, it is proved that the results are equivalent in the complex data domain and in the amplitude domain, further the phase holding property is explained, and the efficiency of the algorithm is improved. Secondly,an easily realized technique to determine parameter is descriked,which can effectively suppress the noise and protect the object.Finally,the experimental results of the simultion and MSTAR(Moving and Stationary Target Acquisition and Recognition) images show that the algorithm is effective.