The time-reversal method, as a wave signal processing technique, has shown great potential in the field of wave reconstruction in recent years. However, existing studies have mostly focused on using the time-reversal method to reconstruct wave trains under specific water depth conditions, without considering the influence of water depth variations on time-reversal wave train reconstruction. In this study, a high-precision two-dimensional numerical wave tank is established based on the open-source smoothed particle hydrodynamics (SPH) model DualSPHysics. Through numerical experiments of time-reversal wave train reconstruction under different water depth conditions, the influence of water depth variation on the evolution of the wave elevation and the time-frequency characteristics of the target wave train is analyzed in detail. This study not only verifies the reliability of the DualSPHysics model in simulating strongly nonlinear wave problems but also provides important data support for the engineering application of the time-reversal technique under varying water depth conditions, which is of significant importance for improving the safety assessment capability of ships and offshore structures subjected to strongly nonlinear waves.