Using the inverse magnetostrictive effect of materials and the law of electromagnetic induction, the vibrational energy in an environment can be converted into electric energy. However, the existing energy conversion models are mainly valid under constant temperature conditions. In this work, the vibration of a machine tool spindle is used as the excitation signal. Besides, based on the magneto-mechanical coupling model and considering the influence of temperature, a magneto-mechanical-thermal multi-field coupling model is established, and the relationship between the vibration signal and induced electromotive force is obtained. The experimental results show that the output electromotive force is 190,160, and 120 m V for temperature changes of 40 °C, 60 °C, and 80 °C, respectively, which is in agreement with the simulation results. Furthermore, the maximum error rate is 0.0244, thus confirming the validity of the theoretical model. Through the theoretical and experimental analyses, it is concluded that, as the surrounding temperature increases, the converted electromotive force output by the energy device gradually decreases.