<p>Accurate numerical simulation of underwater explosions requires an appropriate mesh design that balances computational accuracy and efficiency. To address this issue, a gradient meshing strategy characterized by a mesh gradient coefficient is proposed and systematically evaluated using ANSYS/LS-DYNA simulations. The effects of explosive charge, mesh size, scaled distance on shock wave peak pressure are investigated by comparing numerical results with empirical predictions. The research results indicate that: The use of a larger mesh size can still meet the calculation requirements in the case of a large number of explosives; When the scaled distance is greater than 0.4&#xa0;m/kg^1/3, as the gradient coefficient increases, the error between the simulated value and the empirical formula calculation value increases, independent of the starting position of the gradient mesh. In this case, a smaller gradient coefficient needs to be selected to meet the calculation accuracy. It is recommended to take a mesh gradient coefficient of 1.02; When the scaled distance is less than 0.4&#xa0;m/kg^1/3, the different starting positions of the gradient mesh have a significant impact on the number of model elements and computational efficiency. At this time, the gradient mesh starting position is used to divide the model mesh at the scaled distance of 0.4&#xa0;m/kg^1/3, with a mesh size of 1/3 of the explosive radius, which can improve computational accuracy while ensuring computational efficiency.</p>