The invention discloses a novel digital watermarking method based on matrix Schur decomposition and aims to change the current situation that a current digital watermark is in the form of a binary image or a grayscale image, wherein the requirement of adopting a color digital image as a digital watermark is met. According to the technical scheme of the invention, the method comprises the steps of firstly, conducting the dimension-reduction treatment on a color host image to divide the image into 4 * 4 image blocks; secondly, performing the matrix Schur decomposition on each image block, and determining a maximum energy element in an upper triangular matrix thereof; thirdly, modifying the maximum coefficient of the upper triangular matrix based on the coefficient quantization technique so as to embed the encrypted color watermark image information is embedded into the color host image; fourthly, realizing the purpose of blind extraction during the watermark extracting process only based on the host image containing the watermark, without the help of an original watermark or an original host image. The above method is good in watermark invisibility, strong in robustness and high in execution efficiency. The method enables the right protection for color digital images as digital watermarks.