Abstract: High-power ultrasound, owing to its unique combination of physical and chemical effects, has emerged as a powerful tool for enhancing both hydrometallurgical and pyrometallurgical processes. The primary mechanisms for such enhancement involve acoustic cavitation, acoustic streaming, and chemical reactions. Collectively, these factors improve mass transfer at liquid–solid interfaces and increase reaction rates, facilitate the migration and removal of inclusions in high-temperature molten systems, and promote the refinement of solidification microstructures, thereby enhancing the overall performance of metallic products. Of late, the advancement of computational fluid dynamics (CFD), multiphysics coupling modeling techniques, and high-performance computing techniques has positioned numerical simulation as a crucial method for elucidating the complex interaction mechanisms of high-power ultrasound in metallurgical systems. This paper presents a comprehensive review of the latest progress made in the field of numerical simulation of high-power ultrasound, focusing on two representative domains: hydrometallurgy and pyrometallurgy. In hydrometallurgical applications, the simulations indicate that ultrasonic irradiation produces localized high-intensity cavitation regions coupled with stable acoustic streaming structures in the liquid phase. These hydrodynamic phenomena significantly reduce diffusion resistance, enhance metal leaching efficiency, and improve nucleation behavior, thereby enabling more uniform coating during electrodeposition. Furthermore, the simulation results suggest that ultrasound can be used to precisely regulate flow patterns within the leaching and plating reactors, affording optimized reaction kinetics and improved product quality. In pyrometallurgical processes, the numerical models show that high-power ultrasound modifies the molten metal flow field, shortens homogenization time, and increases the inclusion removal efficiency. During the solidification stage, ultrasound generates a more uniform temperature and solute distribution, suppresses the formation of coarse dendritic structures, and promotes the formation of finer, more homogeneous grain morphologies, which directly contribute to superior mechanical and service properties. The combined effects of ultrasonic agitation and thermosolutal field uniformity have been quantitatively described using advanced simulation methods, enabling precise prediction of microstructural evolution under various operating conditions. From a methodological perspective, the integration of finite element methods (FEM), finite volume methods (FVM), and multiscale coupling strategies has enabled the quantitative evaluation of spatial acoustic pressure distributions, temporal cavitation intensity evolution, and thermo–fluid–solid coupled interactions in both laboratory-scale and industrial-scale systems. By systematically varying ultrasonic parameters—such as frequency, power density, transducer arrangement, and immersion depth—along with reactor geometry, the simulations provide actionable insights for optimizing acoustic field uniformity, minimizing energy dissipation, and tailoring reactor configurations to the specific demands of metallurgical processes. Such modeling frameworks facilitate the design of high-efficiency ultrasonic reactors and offer predictive capabilities that significantly reduce the costs of industrial process development by trial-and-error. Overall, numerical simulation of high-power ultrasound serves as both a visualization tool and a quantitative analytical framework for elucidating metallurgical field-enhancement mechanisms. The knowledge obtained from the simulation studies lays the foundation for process optimization, energy efficiency improvement, and industrial scale-up design. This knowledge also provides valuable parameter guidance and engineering strategies for the successful integration of ultrasonic technology into green, high-performance metallurgical systems. Future research must focus on closer integration of simulation and experimental validation, the development of high-fidelity, cross-scale, multi-field collaborative models, and the study of robust acoustic field control strategies in complex and variable industrial environments. These advancements should accelerate the large-scale application of high-power ultrasound in sustainable metallurgy, contributing to the development of traditional metallurgical processes towards processes with higher efficiency, lower environmental impact, and stronger competitive advantage.