Abstract: Considering the characteristics of human visual system, this paper presents a plain block selecting standard in DCT domain based on visual acuity. This standard excels the frequently used block variance and SNR measurements. Based on the standard, the computational complexity of the fractal image compression is reduced by selecting out the uniform parts in the DCT domain and encoding output the direct current directly without any fractal matching. For encoding time further reducing, the frequency response of human visual system is introduced in the DCT domain to classify the picture blocks and similar blocks and the visual effects of the decoded images are guaranteed in the matching computation of redundancy filtering. Experiment shows that provided with the same compression ratio, the encoding time is greatly reduced with improved PSNR and much better visual effect.