The theory and algorithm of digital watermarking based on DCT transform domain was introduced. A kind of digital watermarking imbedded algorithm realized in discrete Fourier Transform was proposed based on the related theoretical models, which could be used anti-counterfeiting of printed materials. Study results showed that this algorithm has better anti-attack ability than traditional LSB algorithm and Patchwork algorithm. Systematic watermark imbedded algorithm and watermark extraction procedure design were given. Practice proved that digital watermark algorithm based on DCT transform domain can ensure the invisibility of the watermark and the good robustness, which can realize digital copyright protection for printed image carriers and can detect the invisible mark imbedded in printed images by this method. The experiments verified the feasibility, reliability and effectiveness of this method. The purpose was to provide reference for copyright protection of printed materials.