Environmental temperature is an important factor which influences the optical antenna system in orbit. When the temperature changes, the curvatures of the mirrors and the distances between lenses can vary, leading to the reducing of the coupling efficiency of spatial light into single model fiber. Assuming that temperature cannot change the imaging quality except for defocus, the model of influence of temperature on coupling efficiency is established for reflection-type antenna. Based on the model, the numerical simulation of the coupling efficiency is delivered. In order to verify the model, the related experiment is done. The results show that the calculated value is in agreement with the experimental results. When the temperature difference increases to 2 ℃, defocus value enhances to about 52 μm and the coupling efficiency reduces to about 10%. The results have an important contribution to the design of the optical receiving antenna of space optical communication.