There are different kinds of mirror in the space instrument. Sometimes, engineers use filling glue to fill the small gap of the lens and its frame. Thus the structure may be more stable. However, this kind of method could also bring some new problems. Because of different thermal expansion coefficient of the lens and frame, the thermal deformation may be different during the temperature change, which will affect the surface accuracy of the lens and the vibration response. The thickness of glue block and the distributed form of the glue are the key factors. The paper focused on these factors and did some simulations to find out how these factors affect the surface accuracy and fundamental frequency. Then, the paper gave some proposals on this issue.