Abstract: A new and effective improved encoded algorithm based on zero-tree wavelet is proposed, which codes the wavelet coefficients with sorting method according to the Human Visual System (HVS) that we human pay more attention to the edge and flat region of one image than to the texture region.Simulation results show that the algorithm we proposed performs better than that of EZW in image visual quality as the reconstruction image of the improved method has more clear edge because more bits are used to code the coefficients of the edge and flat region.