With the aim to decrease the gravitational distortion and stress for the large aperture optics, a novel mounting configuration was proposed, analyzed and optimized. The effects of the design factors of external load, supporting surface topography and supporting width were studied by using the Finite Element Method (FEM), the changing trends of the distortion and stress with these varying factors were obtained, respectively. More over, orthogonal tests of the influence of these factors were carried out, consequently, the regression analysis of the test results were processed, and the mathematical models for comprehensively considering the coupling effects of these factors were received. Further more, the optimization of the mounting configuration, based on the mathematical models and additionally considered the engineering specifications, was performed, and the optimal configuration was figured out. The numerical results showed the feasibility of the mounting configuration in the aspects of decreasing the gravitational distortion and stress.