随着计算机网络的迅速发展，发生了翻天覆地的变化，数字信息的保护已是一个刻不容缓的问题，由于数字内容很容易复制，修改，网络上的数字内容分发的，有很多的盗版，侵权行为，知识产权保护，以抵抗各种侵权行为，近年来一直是世界上一种新的信息安全技术的提出，数字水印技术，它是一种新的数字信息技术为数字文件的特定著作权利益的保护。现在流行的水印算法在国内外主要是基于空间域和变换域，从综合性能比较，变换域的方法更为优越，目前占主要地位，未来的趋势为变换域方法为主流。本文提出了一种离散余弦变换（DCT）基于变换域的彩色图像水印算法，从低频部分和高频部分的变换后的图像，水印信号嵌入到低频部分，可以保证水印的鲁棒性。-With the rapid development of computer network, happened to turn the world upside down change, the protection of digital information has been a brook no delay problem, due to the modification of digital content is very easy to copy, distribute, digital content on the Internet, there are a lot of piracy, infringement, protection of intellectual property rights, to resist all kinds of tort, in recent years has been is a new information security technology, digital watermarking technology, it is a kind of digital information technology for specific works of digital document right to protect the interests of the. Watermarking algorithm now popular at home and abroad is mainly based on spatial domain and transform domain, from the comparison of comprehensive performance, the transform domain approach is more superior, currently occupies the main position, future trends in the transform domain method for the mainstream. This paper presents a discrete cosine transform (DCT) color image waterm