Abstract: Having considered the influence to water continuity and its energy balance due to the thermal water diffusivity and the isothermal vapor diffusivity, the control equations for analyzing coupled thermo-hydro-mechanical phenomena in saturated-unsaturated porous media are improved. Taking the Task3 BMT1 of the international co-operative project DECOVALEX III as a simulative object, the numerical analysis for the coupled thermo-hydro-mechanical processes in near field of a conceptual nuclear waste repository was carried out by using a program of finite element method developed by the author, and the changes and distributions of temperature, saturation, pore pressures and principal stresses in the engineered barrier were investigated. The part numerical results were compared with the computation data in Task3 BMT1 obtained by THAMES code of Japan, and it is shown that the regulations of both results have certain identity qualitatively and quantitatively, but there exists some differences between them. The reasons are analyzed and some conclusions are obtained.