When analyzing and optimizing the performance of thermoelectric (TE) devices in theory, Seebeck coefficient, thermal conductivity, and electrical resistivity are indispensable TE properties. However, most manufacturers do not provide or overestimate these data. Under the consideration of temperature dependence, this paper discloses an experimental measurement approach to estimate the equivalent Seebeck coefficient, thermal conductivity, and electrical resistivity of a TE module. A thermal resistance network is also established to work out the hot and cold side temperatures of TE legs. Based on a designed test bench, required temperature and electrical parameters in both open circuit and closed circuit are measured and recorded, where the data of open circuit are used to calculate the equivalent Seebeck coefficient and thermal conductivity, and the data of closed circuit are used to calculate the equivalent electrical resistivity. To eliminate the error of parasitic internal resistance, a thermal-electric finite element model is adopted to modify the equivalent electrical resistivity. The modification results indicate that the equivalent internal resistance is about 1.033 times the real internal resistance, and the ratio is related to the working temperature. This work provides a new idea to obtain the TE material properties via an experimental test.