Abstract: In order to explore the thermal characteristics of the linear feed axis of the CNC milling machine for spiral groove and reduce the workload of arranging the temperature sensor during the operation of the machine tool, the finite element simulation analysis method is used to realize the thermal characteristics research work and explore the main heat source of the machine tool feed shaft. Three-dimensional model of the linear feed shaft is established and simplified, and the mesh is divided. After the heating load is applied according to the working environment and the boundary conditions are determined, the simulation results of the temperature field are obtained. In order to verify the accuracy of the simulation model, the sensor measuring points are arranged according to the temperature field distribution obtained from the simulation analysis, and the temperature rise measurement experiment is carried out. The experimental results show that the maximum error of steady state temperature is about 6%, and the transient temperature variation trend is consistent with the experimental results. Therefore, the established finite element model can provide theoretical guidance for the in-depth analysis of the thermal characteristics of the linear feed shaft.