In this study, numerical methods are used to investigate the flow and temperature fields of the air-cooled motorized spindle. The wind speed effects on the motorized spindle temperature and the relationships between the rotating speed, vibration and noise are studied experimentally. The purpose of this work is to provide the basis for optimization design of the air-cooled motorized spindle. First, the boundary conditions are defined and the wind speed in the heat sink groove, fluid field of the fan area and temperature distribution of the spindle in the thermal steady state are predicted by the finite element method. Second, the temperature, wind speed, vibration of the key points on the motorized spindle and the noise are measured experimentally. The results show that the wind speed of the fan area is high in the center and low near the wall. The spindle temperature is higher in the area of contact with the rotor and the front bearings, while changes in the heat sink section have little effect on the wind speed. It is found experimentally that the vibration, noise and temperature increase with rotating speed. The numerical and experimental results are consistent. It is suggested to improve the design of the motorized spindle through optimizing the blade structure to decrease the temperature, vibration and noise.