Abstract: This paper focuses on the ultra-low thermal deformation requirements of the main support structure of the gravitational wave detection telescope. It proposes a method to reduce the thermal deformation of the truss support structure by designing CFRP (carbon fiber reinforced polymer) layers to modify the material's thermal expansion coefficient. Additionally, to meet the alignment performance requirements of the telescope, a segmented design scheme for the structure is presented. The paper begins by analyzing the advantages of CFRP, existing methods of thermal dissipation, and the research progress both domestically and internationally. It determines the three-segment telescope design using CFRP as the support material and establishes design criteria. Next, mathematical models for "material-thermal deformation" and "truss structure-thermal deformation" are developed. Optimization is conducted for material layering and structural design, resulting in an optimized solution. Furthermore, CFRP materials are applied to the support structure, and a segmented main support structure design scheme is proposed to reduce the difficulty of structural processing and alignment. The overall structure is analyzed. The analysis results demonstrate that, in terms of mechanical performance, the overall structure's natural frequency and maximum gravity-unloading deformation meet the requirements of the main support structure. In terms of thermal deformation, the optimized design based on CFRP layering exhibits a thermal deformation that is 27.15% of the conventional layering scheme, 6.42% of the Invar material support rod scheme, 11.50% of the SiC support rod scheme, and 3.21% of the titanium alloy support rod scheme. This indicates that the optimized design can significantly reduce the structural thermal deformation.