Abstract: With the increasing integration of electronic devices and components, heat dissipation is becoming more and more challenging. Semiconductor thermoelectric coolers (TECs) have become a cost-effective and flexible cooling solution due to their compact structure and simple control method. In this article, a constant temperature platform is constructed to simulate the heat sink in electronic devices. Through using the heating ceramics to simulate the thermal load, the heat dissipation performance of TEC in high-temperature environments are studied by experiments. The results show that within the test temperature range, the TEC can always absorb the heat when driven by current whether the temperature at the TEC's heat absorption side is higher than that at the heat dissipation side. When the heat load is 120 W, the TEC can reduce the temperature at the heat load surface by up to approximately 22.5 ℃, with a useful heat absorption power of about 50.9 W at the heat absorption side. Moreover, the higher the platform temperature, the better the cooling effect of the TEC when compared by the useful heat absorption power.