Due to high rotation accuracy, high dynamic stiffness, high vibration damping and long life, high-speed spindles supported by hydrodynamic and hydrostatic hybrid bearings are widely applied in the field of high-speed precision machine tools. The basic structure and working principal was detailed introduced, and then demonstrated a series of models and specifications of motorized spindle manufactured by FISCHER company in Switzerland. The finite element model of high-speed motorized spindle was built up and carried out thermal analysis to study the heat generation and heat transfer. With the help of ANSYS finite element software, the temperature field distribution and the temperature rise condition for motorized spindle were analyzed. The result indicates that the front bearing has a higher temperature than that of back bearing. The maximum temperature of inner ring is bigger than that of outer ring.