The work aims to put forward a new DCT self-adaptive watermarking algorithm with strong robustness to improve the anti-attack performance of color image digital watermarking. In the algorithm, Arnold transform was used to preprocess the watermark image, and the intensity factor was adaptively selected. According to the principle of DCT transform and by means of the formation process of its DC coefficient, DCT transform was not required and 8×8 blocked DC coefficient could be calculated in the spatial domain. According to the distribution characteristics of DC coefficient modifiers, the watermark embedding was directly completed in the spatial domain. The digital watermarking algorithm had good transparency and robustness, and it also had strong robustness regarding painting, rotation, cutting, superimposed noise and other common assaults. The algorithm can ensure watermark concealment and it is also able to resist a certain level of attacks, which meets the needs of copyright protection and digital anti-counterfeit.