Abstract: The space-borne antenna is affected by the heat flow in orbit. The antenna will experience periodic alternating high and low temperatures, resulting in thermal deformation of the antenna reflector. In order to ensure the stable operation of the space-borne antenna, a dual reflector parabolic antenna was selected as the research object in this paper. The finite element method was used to analyze the in-orbit temperature field of the antenna under high temperature. The temperature loads distributed on the antenna were then mapped as the boundary conditions to the structural field for thermal deformation analysis. The effects of the material properties, the aluminum honeycomb core thickness, the carbon fiber layer thickness, and the constrained positions of the reflector on the thermal deformation of dual reflector parabolic antenna were analyzed in detail to provide a theoretical reference for the optimization design of the space-borne antenna structure.