Abstract: An algorithm for color image embedding the watermarking was proposed based on a new HSI color space. The image was transformed from the RGB color space to the HSI color space, and divided into non-overlapping 8×8 blocks on every component of the original color image, DCT was performed to every block. A robust watermark for copyright protection was transformed by Arnold transformation to improve the security.Through the application of the watermark embedding technology, it can effectively resist the color depth transformation attack, and it is close to the explanation of the color of the human body and is effective to prevent tampering. The results can provide technical support to reflect good invisibility and robustness, and effective to identify the copyright of image.