Sonar detection technology has been widely used in underwater structure detection. Affected by the complex underwater environment, sonar images usually have substantial problems such as low resolution, serious noise interference, fuzzy edge details, and poor texture information. In order to solve these problems, this paper proposes a fusion denoising algorithm based on improved anisotropic guided filtering and Wiener filtering. Firstly, the local structural similarity index was introduced into the traditional AnisGF as a weighting factor to achieve denoising while retaining more edge structure information. Secondly, the Bayesian optimization method was used to determine the SSIM weight of Wiener filtering. Finally, AnisGF and Wiener filtering were combined for joint denoising of sonar images. The experimental results show that the proposed algorithm has 9.5%, 4% and 10% improvements in mean square error, peak signal-to-noise ratio and structural similarity index compared with the traditional algorithm.