<p>The dynamic characteristics of motorized spindle change in real time under the influence of the magnetic-thermal coupling physical field. In order to realize dynamic updating of dynamic characteristic datas of motorized spindle under magnetic-thermal coupling, a dynamic modeling method for magnetic-thermal coupling of motorized spindle based on digital twin is proposed. Considering the impact of temperature rise on winding resistivity and core thermal conductivity, a twin database and service platform are established. The database and service platform facilitate bidirectional interaction between the twin mechanism model and motorized spindle’s data model. A magnetic-thermal coupling model for motorized spindle is established using the twin database and service platform. Following this, a dynamic model for motorized spindle bearing-rotor is developed. The real-time changes in temperature rise, unbalanced magnetic pull, structural deformation, and dynamic characteristics of motorized spindle are analyzed. The results show that maximum frequency domain error between the data-driven model and experiment is 2.49 % less than that between traditional model and experiment. The dynamic simulation results of the magnetic-thermal coupling of motorized spindle driven by twin are closer to entity.</p>