The aberration correcting ability of deformable mirror is directly affected by the performance of its supporting structure. A structure form of deformable mirror for space camera was described, and different structures of support base were analyzed from the aspect of material properties and manufacturing process, it proves that solid structure made of CFRP is superior to rib-board structure made of TC4, and stiffness ratio of support base material is the main factor of deformation caused by gravity, while the difference of CTE between the materials of support base and reflector affects thermal deformation mostly. Comparing with three-point edge support, the scheme of three-point back support was used to improve the collapse phenomenon caused by gravity, with the RMS value of gravity in z direction decreased by 73%, from 15.38 nm to 4.17 nm, and homogenize the thermal deformation, with the RMS value of 4 ℃ rise decreased by 12.5%, from 3.68 nm to 3.22 nm, and its first order frequency is also improved from 1 513 Hz to 1 982 Hz. This indicates that the dynamic and static stiffness and thermal stability of this deformable mirror satisfies the application requirement for space camera.