In this paper, we have carried out a validation study on two optical-mechanical integration modeling methods, including the mirror pose reconstruction method that only considers the spatial pose change of mirror surface units under load (ignoring the elastic deformation of the mirror surface) and the plane element substitution method proposed in this paper. The proposed method works by converting the reflecting mirror surface of the solar concentrator into many discrete plane elements and directly establishing the geometric optical information from deformation information of plane elements, so as to realize the data unification and integration of the optical-mechanical analysis, and the integration model of optical-mechanical information of the reflecting mirror is established. The results of focused flux distributions from the two optical-mechanical integration methods are verified jointly and compared with the measuring results from the experiment of solar concentrator under load, which fully demonstrates the effectiveness of the two methods. When the elastic deformation of all reflecting mirror surfaces in the concentrator is large, the mirror pose reconstruction method cannot accurately predict the optical performance of concentrators. However, the plane element substitution method can fully consider any deformation (elastic deformation and rigid body displacement) of the reflecting mirror under load and accurately predict the focused performance with its universality and simplicity. Experiments show that for low focused flux density, it is feasible to use rough white paper (printing paper) as the Lambertian surface to measure the focused flux density.