For the use of mirrors in space camera back support, the change in temperature will cause a partial supporting surface accuracy of the hole near the lower annular formation of local defects, which affect the quality of the optical system corresponding to the imaging field of view. In order to improve the adaptability to temperature mirror support structure by increasing the flexibility, and reduce the local connection stiffness, design of a flexible structure is optimized. Mirror assembly simulation for analysis, in the mirror assembly temperature 4℃ lower case, optimize the structure of the reflector around the middle hole of the support as the local scene shaped PV=4.9 nm, RMS=1.0 nm. Compared with the former (PV=16.6 nm, RMS=3.5 nm), and its accuracy is improved by 3 times, the global field shape PV=16.3 nm, RMS=3.2 nm. Compared to before optimization (PV=30.2 nm, RMS=5.2 nm), its accuracy is improved. Mirror assembly in the 1 order frequency before the optimization is 191 Hz and after the optimization are 183 Hz, basically unchanged. Mirrors in various gravity conditions, depending on the global scene shaped to optimize PV and RMS values before and after the basic structure remains unchanged, which illustrate that the new flexible support structure ensures the mirror dynamic, static stiffness, improve the temperature adaptability of mirror, reduce the influence of temperature changes to the mirror support hole near the local surface shape accuracy, and improve the imaging quality of local field optical system and imaging quality of all field goal.