The principle and theory of SLCCA (Significance Linked Connected Component Analysis) coding technology has been further studied in this paper. To enhance SLCCA, we introduce distance-first significance-linked connected component analysis and a combined extension and arithmetic code for symbol sequence. An enhanced SLCCA coding system is constructed. Its PSNR performance is compared with both SLCCA and JPEG2000 on numerous 512×512 gray-scale natural images at three different bit rates, i.e., 0.3, 0.6 and 0.9 bits per pixel. On average, SLCCA+ is superior to SLCCA by 0.45 dB and significantly outperforms JPEG2000 by 3.69 dB. Detailed algorithm and further improvement will be given in a separate paper.