Abstract: Based on the spindle error analyzer and high-precision digital temperature sensor, the spindle thermal characteristic test sysstem is built, and the spindle thermal characteristic test method and process are given. The spindle thermal characteristics of vertical machining center at different speeds were tested. Based on the spindle thermal error, speed and temperature data of key points, the conclusion that the axial thermal drift error of the spindle q has an exponential relationship with the speed is obtained, and the optimal temperature measurement point selection method based on pearson correlation coefficient is given; It is concluded that the thermal drift error of the spindle in Y direction is linear with the rotation speed, and the temperature difference between the upper and lower end faces of the spindle box is the main cause of the thermal tilt deformation of the spindle in Y direction. The relationship between thermal characteristic index of spindle and machining accuracy is analyzed.