The current study aims to mitigate the prevalent problems of excessive mass and energy usage in screw vacuum pump rotors, more specifically, the carbon fiber reinforced polymer (CFRP) rotors. An innovative approach of thermodynamic analysis was introduced to assess the performance of these rotors under specific operating conditions. This was coupled with a thermal-structural analysis and heat transfer optimization to provide a comprehensive perspective on the system's thermodynamic behavior. Examination of the patterns of deformation, stress distribution, and heat transfer characteristics revealed significant insights for rotor structure optimization. Of particular note was the pivotal role of the temperature field, which was found to be an influential determinant of the rotor's deformation, stress, and heat transfer, as discerned from a comparison between static, thermal-structural coupling, and thermodynamic analyses. The optimized rotor structure, while displaying increased deformation and stress due to reduced stiffness, was confirmed to adhere to the design and assembly prerequisites for rotors. In conclusion, this thermodynamic approach contributes novel insights into lightweight design and enhancement strategies for screw rotors, with implications for various practical engineering applications.