Abstract: According to the related theory,the momentum equilibrium equation,the continuity equation for water,the energy balance equation and the elastoplastic matrix for the vapor-liquid two-phase unsaturated porous rockmass in geological disposal of the high level radioactive nuclear waste were established.By using the Galerkin method all the governing equations were discretized in the space domain and in the time domain respectively,then a two-dimensional FEM code for analysis of coupled thermo-hydro-mechanical elastoplastic processes was developed tentatively.Through the numerical computation for a conceptual nuclear waste repository it was shown that after geological disposal of the high level nuclear waste the temperature and the liquid phase saturation in the buffer zone would raise,and in the same zone obvious concentration phenomena of stresses,pore pressures,temperature,liquid phase saturation and vapor phase saturation would occur in scores of years.