Supercavity technology is one of the key technologies for underwater high-speed vehicles as it can reduce their resistance and increase their speed. In this paper, the current development of numerical calculation in supercavitation flow is reviewed. First, the numerical calculation methods are introduced, including modeling and numerical simulation methods. The modeling methods are based on the potential flow theory, which develops into the free streamline theory and linear theory for two-dimensional hydrofoils, and Logvinovich’s principle, which can be used to calculate the three-dimensional shape of the supercavity. The numerical simulation method is based on computational fluid dynamics. The finite volume method is typically used for the supercavity problem. The multiphase flow and turbulence model significantly affect the simulation results, and the limitation of the potential flow theory is overcome by combining the cavitation model and acoustic model. The supercavitation flow and load are predicted for undersea vehicles with different configurations considering the effects of multiphase flow, mass transfer, and viscosity. Finally, the recent developments in numerical research are introduced with regard to several key factors, including the natural cavitation number, ventilation and inflow conditions, and vehicle shape. These factors affect the shape of the supercavity, and the ventilation parameters and inflow conditions affect the closure mode. This paper provides a reference for subsequent research on the numerical calculations of underwater supercavitation flow.