The invention discloses a non-strain fixing-mounting structure of an astronautic camera special-shaped prism, which comprises a left baffle (1), a special-shaped prism framework (2), a special-shaped optical prism (3) and a right baffle (5); the special-shaped optical prism (3) is mounted in the special-shaped prism framework (2); the left baffle (1) and the right baffle (5) are respectively blocked at the two sides of the special-shaped prism framework (2); strain-removing thermal treatment is carried out on the special-shaped prism framework (2), the left baffle (1) and the right baffle (5); the contact parts between the top part and the bottom part of the special-shaped optical prism (3) and the special-shaped prism framework (2) are provided with patches (4); the left baffle (1) and the right baffle (5) are provided with baffle glue injecting holes (6). As an integral opening structure is adopted by the invention, a refine linear cutting mode is adopted in processing; simultaneously strain-removing treatment is adopted to the framework structure, thus leading the strain of the special-shaped prism framework to the smallest while ensuring the processing precision, thereby avoiding the structure deformation to affect the optical performances of the prism.