本文结合DCT变换的特性，利用分形的Peano一hilbert扫描曲线，对基于DCT变换的图像编码方法进行了研究，并提出了改进方法。主要工作分为两个部分: 一是在分块DCT基础上的改进。对分块后生成的各图像块矩阵，不直接作二维DCT变换，而是先进行扫描，使之重排成一维向量，再进行一维DCT变换，这样可以减少运算量。 其次是对层次余弦变换编码部分的改进。使用层次DCT变换与零树编码相结合的方法，并在扫描编码过程中，按Peano一hilbert扫描顺序进行编码。这样不仅可以减少“块效应”，而且可以加快编码速度。-this paper the characteristics of DCT, using fractal Peano a Hilbert scanning curve, the DCT-based image coding method for the study and improvement of methods. The work is divided into two main parts : First, the DCT block on the basis of improvements. Right after block production of the image block matrix, not for direct two-dimensional DCT, but first scan, so they line up in a heavy-dimensional vector and then a peacekeeping DCT, thus reducing the amount of computation. Secondly, the level of cosine transform coding some of the improvements. The use level of DCT and zero tree coding combination of methods, coding and scanning process, according to a Hilbert Peano code scanning sequence. This will not only reduce the "blocking effect" but we can speed up the coding speed.