Abstract: In order to reveal the 3D spatial morphology of the seabed terrain environment and seabed targets in 360°, a 3D reconstruction method is designed based on BFGS(Broyden-Fletcher-Goldfarb-Shanno) algorithm and ADMM(alternating direction method of multipliers) for SFS(shape from shading). The BFGS-ADMM and PCG(preconditioned conjugate gradient) iterative optimization algorithms are used to iterate the 2D side-scan sonar images and process the relevant constraints to ensure the consistency and smoothness of the final 3D reconstruction results. After obtaining the 3D reconstructed underwater topography, the 3D reconstruction algorithm index is established, and a series of experimental verification is carried out at the same time to ensure that the proposed SFS 3D reconstruction method is not only theoretically practical and feasible, but also practically effective, and meets the needs of underwater 3D topography reconstruction.