:目前混沌系统与加密技术相结合是现如今最热门的一个课题，虽然有大量的加密算法面世，但是这些加密算法并不成熟，仍然需要进一步的研究。本文采用像素位置置乱变换和像素值替代变换相结合的加密思想，设计出一种基于混沌的数字图像加密算法。引入了整数域上的逆仿射变换，算法中采用二维 logistic 混沌映射相结合的方法，生成多组混沌序列，像素置乱变换与灰度值替换都由这些混沌序列所控制。多混沌序列产生的密钥空间大于单一的混沌序列所产生的密钥空间，因此本文研究的算法加密强度很高。-The current chaotic system with encryption technology combined is now one of the hottest topics, although there are a number of encryption algorithms available, but these encryption algorithms are not ripe, still need further study. In this paper, the pixel position and the pixel value Scrambling alternative encryption ideological transformation combining design a digital image based on chaos encryption algorithm. The introduction of the inverse affine transformation integer domain, the algorithm uses a two-dimensional logistic chaos mapping method of combining to produce multiple sets of chaotic sequence, scrambling transformation and pixel gray values are replaced by the chaotic sequence control. Key space more chaotic sequence is greater than the key space of a single chaotic sequence generated by the algorithm to encrypt and therefore high strength paper.