Sparse coding has been widely used in complex value image demising. In recent years, the proposed block sparse coding has more advantages in noise filtering and noise reduction because it can make full use of the similarity of patches in the same block. In this paper, a K-means clustering method based sparse demising algorithm for complex image grouping is studied. By improving the clustering algorithm, the grouping effectiveness of K-means algorithm for sparse block coding algorithm is verified. The online complex dictionary training algorithm is used to acquire the coded dictionary quickly, and the sparse coding of block image is realized by using the grouping orthogonal matching pursuit algorithm. By inducing the similarity of the coding in each block, the coding of noise in the block is effectively suppressed and the noise reduction of the complex value image is improved. In order to verify the effectiveness of the proposed algorithm, the demising of simulated and real interferometric synthetic aperture radar images is quantitatively analyzed, which proves that the proposed algorithm has a certain improvement in peak signal-to-noise ratio (PSNR) compared with the previous block sparse coding algorithm. Finally, the real interferometric synthetic aperture radar image is demised, which further verifies the de-noising ability of the proposed algorithm for real noise.