The thermal deformation of high-speed motorized spindle is an important factor affecting machining accuracy. In order to reduce the temperature rise and axial thermal elongation of the motorized spindle, the heat source and thermal boundary conditions of a certain motorized spindle were analyzed, the thermal-structure coupling simulation was carried out by using ANSYS Workbench software, the motorized spindle temperature field and thermal structure coupling field were obtained. An experimental platform was built to test the temperature field and axial thermal elongation of the motorized spindle system to verify the correctness of the finite element model. Finally, 38CrMoAl, ZrO2, Si3N4 and glass ceramics were selected as spindle materials for comparative analysis of thermal structure coupling. The results show that ceramic material is superior to steel in thermal properties, and glass ceramic material has the best thermal performance.