The large aperture laser transmission mirror is a crucial optical unit of the high power solid-state laser in the inertial confinement fusion (ICF) facility. Based on the engineering practice of the SG-Ⅲ facility, the technology status and key problems of the low-stress mounting configuration for the mirror are summarized firstly. Then, a general mechanical model of the deformed mirror is built with the elastic mechanics theory. Furthermore, a brand new low-stress mounting configuration with flexure support is proposed and the mechanical properties of the flexure support are verified with the finite element method and field experiments. The new integrated mirror assembly is designed and the influence of mounting force on surface deformation under the current and the new technologies is studied by comparison. Finally, with combination of the new mounting configuration and the numerical decoupling method of stress-induced deformation, a promising process flow is discussed. The study is of great significance for solving the mounting-induced deformation of the large aperture optical devices, and is expected to provide effective and reliable technical schemes for constructing ICF facility of the next generation.