Abstract: Natural soil often has the characteristics of rheology due to different depositional conditions and stress states. The present paper focuses on investigated the effects of different porosity and permeability coefficient in saturated porous foundation which considered the viscoelastic relaxation times with coupled thermo-hydro-mechanical fields under external load. A two-dimensional coupled thermo-hydro-mechanical dynamics problem for a half-space on an isotropic, uniform, fully saturated, and poroviscoelastic soil (THMVD) whose surface is subjected to either mechanical force or thermal load based on the Biot's wave theory of porous media, Darcy's law, and Lord-Shulman (L-S) generalized thermoelastic theory with Kelvin-Voigt viscoelastic model is investigated. The general relationships among the non-dimensional vertical displacement, excess pore water pressure, vertical stress, and temperature distribution are then deduced via normal mode analysis and depicted graphically. Normal mode analysis is a method using weighted residuals to derive analytical solutions. Via this method, the equation can be divided into two parts without integral transformation and inverse transformation, thereby increasing the speed of decoupling and eliminating the limitation of numerical inverse transformation. The effects of the porosity and the permeability coefficient on the four different physical variables have been investigated. It can be shown that: whatever load is being considered, the variation of load frequencies have obvious effect on all the considered physical variables; the porosity and permeability have the most obvious influence on non-dimension excess pore water pressure. When thermal loads were considered only, the variation of porosity and permeability coefficient had barly effect on non-dimension temperature. This proposed derivation method can be widely applied in the geotechnical engineering field, especially with regard to the mechanical and thermal behaviors of commercial buildings, high-speed railways, and highway energy foundations. The research results of this problem can lay a certain theoretical foundation for engineering construction and have a certain guiding significance.