Abstract: Studying the thermal influence of radio telescope and maintaining the thermal stability of the structure are important to meet the high precision requirements of large diameter ground radio telescope, Taking NanShan 26m antenna as the object, the FEMAP software is used to establish the frame structure model, and the boundary conditions are set. Then the temperature field distribution of the antenna in daytime on June 4 is obtained, then coupled with the structure to obtain the thermal deformation. A temperature measurement system is established to compare with the simulation results, The results show that the local maximum temperature is 31.33℃, the maximum temperature difference can be up to 10℃, the maximum displacement can reach 1.8mm, which is consistent with the variation of measured results. Studying the temperature distribution anddeformation effects of the frame provides a reference for temperature compensation and the optimization of the structure.