In the design and production of optical instruments, various kinds of adhesive are used to mount optical element instead of screws, platens and other fixed parts. But in the assembly of high-accuracy lens and large-aperture lens, the effect of gravity and the curing stress of adhesive cannot be ignored, as a result, research on surface deformation of lens by this effect is necessary. In order to shorten design cycle and reduce costs, this paper designed a simulation analysis about lens structure fastened by adhesive (RTV adhesive), which made use of finite element software (Ansys). The analysis result indicated that the deformation was within the limit of permission, and several methods of correcting various aberrations were given. These results can be guideline in the practical work in the assembly of lens. Besides, further research on this item is suggested being launched in the future.