In this study, we construct a model to calculate the thickness of the adhesive layer in the mirror subassembly of a space camera with a blind taper hole based on different boundary conditions. Further, a mechanical model is used to calculate the adhesive layer thickness range at the bonding part that satisfies the design requirements. Using the constructed finite element model, we calculate and fit the corresponding thickness-stress curve of the adhesive layer, and the optimum thickness is observed to be 0.055 mm. Subsequently, the change in the surface of the mirror subassembly is numerically analyzed under the self-weight and temperature-rise conditions in order to verify the surface shape accuracy of the adhesive structure. The temperature load method is employed to simulate the influence of the adhesive layer shrinkage on the surface, and the subassembly tests are performed. The simulation and test results demonstrate that the mirror subassembly exhibits a sufficient capability to resist the interference of the external temperature variation and vibration at an adhesive layer thickness of 0.055 mm, satisfying the design requirements.