The influences of electromagnetic radiation from mobile phones on human health have aroused significant public concern. One of the most serious consequences is the increment of temperature of tissues and organs. Due to the specificity of the research object, numerical methods for electromagnetic and thermal analysis are usually adopted instead of trials. Most of the existing studies adopt a finite-difference time-domain method for electromagnetic and thermal simulation. Moreover, the radiative cooling phenomenon is neglected during the thermal simulation. In this letter, we utilized the finite-element method with tetrahedral elements to get a better modeling of the human head. Furthermore, the radiative cooling is also taken into account by using the radiation boundary condition. Numerical results validate the accuracy and capability of the proposed method.