Abstract: The dynamic response characteristics of saturated porous media are of a great significance in both earthquake engineering and geomechanics fields. Based on the u-p formulation of the saturated porous media, the space-time boundary mapping collocation method is applied to the numerical solution of this problem. This method is a strong-form meshless collocation approach based on the tensor decomposition technique. In this method, two-dimensional dynamic problems are transformed into a three-dimensional space-time domain. And the boundary discrete nodes are used to construct one-dimensional boundary shape functions. The space-time shape functions are then generated via tensor product operations and via moving least square approximations. The method proposed enables global discretization and approximate solutions without the need for traditional time-stepping integration, effectively circumventing the limitation of time step size. The computational accuracy and efficiency of this method were verified through a saturated soil column example. Moreover, no numerical oscillations occurred during the initial stage, demonstrating excellent computational accuracy and stability. Furthermore, the dynamic responses of a two-dimensional saturated soil layer under harmonic loads are analyzed, and the spatial distribution and attenuation characteristics of the pore water pressure, of the vertical displacement and, of the horizontal displacement are systematically discussed. The research results indicate that the space-time boundary mapping collocation method can efficiently and stably simulate the complex fluid–solid coupling behavior of saturated porous media under dynamic loading, showing a strong potential for engineering applications.