Abstract: Thermal deformation of a CNC external thread grinding machine under multiple heat sources was investigated. A suppression method based on active temperature control technology was proposed. Firstly, a simulation analysis of the thermal deformation under internal heat sources was conducted, a simplified structural model was established, and a machine-wide heat generation and dissipation model was created. Secondly, the thermal deformation simulation results under internal heat sources only were extracted. By comparing different layout schemes of temperature control plates on the slide plate, two temperature control strategies were proposed, namely uniform temperature control and differentiated temperature control. On this basis, simulation conditions for thermal deformation under multi-heat source effects were set. Through comparative analysis, an optimized scheme was adopted, which involved symmetrically arranging temperature control plates near the middle of the bed and the slide plate. Furthermore, thermal deformation was numerically analyzed under conditions involving either a single external heat source or multiple heat sources, and the results under multi-heat sources were systematically analyzed. Finally, by analyzing the thermal deformation behavior of the machine structure under single and multi-heat source conditions, it is concluded that the application of active temperature control technology can effectively suppress thermal deformation in CNC external thread grinding machines, thereby enhancing the overall machining accuracy.