Abstract: To investigate the dynamic response of unsaturated soil under moving loads, a soil-water characteristic curve (SWCC) model was established with the considering of deformation caused by applied load. Using this SWCC model, a dynamic governing equation of unsaturated soil, which fully describes the water-force coupling effect of unsaturated soil under dynamic loading was derived. The governing equation was solved using the 2.5-dimensional finite element method (2.5D FEM). The obtained solutions were compared with analytical solutions for single-phase medium, double-phase saturated medium and three-phase unsaturated medium, respectively; which all confirmed the accuracy of the proposed solution method. Computational time analysis for different medium models demonstrated that the 2.5D FEM is an advantageous algorithm for solving dynamic problems of porous medium. Numerical analysis revealed that using the traditional SWCC without the considering deformation would underestimate the vibration intensity of unsaturated foundations.