With the help of Domenicali's equation and the heat flux equation, a finite difference method is directly used to determine the temperature and heat flux distribution profiles in one dimension of a thermoelectric generator simultaneously including the Peltier, Fourier, Joule, and Thomson effects. This calculative method is also used to evaluate the performance of a thermoelectric generator, based on experimental data of thermoelectric materials PbTe1-yIy and PbTe: Na/Ag2Te. The efficiency of the thermoelectric generator as a function of the electric current is calculated and the effects of structure parameters on the performance of the thermoelectric generator are revealed. The method proposed here offers a simple way to properly choose n-type and p-type thermoelectric materials of a thermoelectric generator. (C) 2014 Elsevier Ltd. All rights reserved.