The thermal characteristics of the spindle system of vertical machining center become one of the main factors affecting its machining accuracy. It is particularly important to analyze the thermal characteristics of the spindle system of the vertical machining centers. VMC850E vertical machining center is researched. The API spindle thermal drift error analyzer, advanced capacitive or inductance sensors and contact temperature sensors are used to analyze the relationship between spindle temperature rise and thermal drift. The experimental results show that the radial and axial thermal drift of the spindle increases at the temperature rising stage, and the Y-axis thermal drift is the largest. The thermal drift in all directions decreases at first and then increases. In the process of processing, the requirements of the lubrication and cooling of the spindle are higher.