<p>Giant magnetostrictive actuators (GMA) are receiving increasing attention in the development of actuation devices. The performance of GMA is primarily determined by output displacement accuracy, which is governed by electro, magnetic, thermal and mechanical interactions. Therefore, a multiphysics model is established to describe the output performance of the GMA. Firstly, an uneven magnetic field model of the GMM is formulated by considering the magnetic field induced by the energized coil and accounting for the eddy current effect; secondly, the thermal network model is established by considering the ohmic loss of the coil, as well as the eddy current and hysteresis losses of the GMM; finally, the mechanical output model of the GMA is constructed by considering the influence of temperature on both magnetostrictive displacement and thermal expansion. Simulation analysis and experimental verification demonstrate that the constructed model accurately represents the temperature behavior and displacement performance of the GMA under various operating conditions. Research findings offer guidance for the further development of GMA across different application contexts.</p>