<p>The local time-stepping (LTS) algorithm is an adaptive method that adjusts the time step by selecting suitable intervals for different regions based on the spatial scale of each cell and water depth and flow velocity between cells. The method can be optimized by calculating the maximum power of two of the global time step increments in the domain, allowing the optimal time step to be approached throughout the grid. To verify the acceleration and accuracy of LTS in storm surge simulations, we developed a model to simulate astronomical storm surges along the southern coast of China. This model employs the shallow water equations as governing equations, numerical discretization using the finite volume method, and fluxes calculated by the Roe solver. By comparing the simulation results of the traditional global time-stepping algorithm with those of the LTS algorithm, we find that the latter fit the measured data better. Taking the calculation results of Typhoon Sally in 1996 as an example, we show that compared with the traditional global time-stepping algorithm, the LTS algorithm reduces computation time by 2.05 h and increases computation efficiency by 2.64 times while maintaining good accuracy.</p>