In order to improve the security and anti-attack ability of digital watermarking algorithm, combining the advantages of hyperchaos and Slant transform, a robust watermarking algorithm based on hyper-chaotic and Slant transform is proposed. Firstly, the watermarking image is encrypted by hyper-chaotic, which improves the security of the image to be embedded. Secondly, the original cover image is divided into non-overlapping blocks of size 8×8 and the Slant transform is performed on each block. Finally, the encrypted watermarking image is embedded into the DC coefficient and the middle frequency coefficient after Slant transform. A large number of simulation results show that the proposed algorithm has better transparency and robust performance for JPEG compression, noise, filtering, scaling, contrast adjustment and other attacks. Compared with the similar algorithms, the proposed algorithm has better robust performance.