Abstract: To study responses of unsaturated rock masses to coupled THM processes,the governing equations of coupled THM behaviors in unsaturated rock masses were derived by using the equivalent continuum model.The governing equations include those for thermal,hydrological and mechanical fields,and are based on the conservation equations for fluid and solid masses,linear momentum and energy,as well as the corresponding state equation and constitutive equations.In the derivation,thermal elasto-plastic constitutive relationship,rather than the assumption of local thermal equilibrium,was adopted,and the effect of temperature gradient on hydrological processes was taken into account.