Abstract: Thermal behavior of the 2.45GHz lower hybrid wave (LHW)antenna in EAST is investigated. The temperature distribution of the LHW antenna is obtained using the ANSYS code. The thermal stresses and displacements due to thermal loads are calculated. The temperatures measured by the thermocouples in the experiment are also presented. All the results of the simulation are discussed. The simulated results offer guidance for the design and manufacture of the antenna.