Large view field off-axis three-reflector system and adjusting method

The invention relates to a large view field off-axis three-reflector system and an adjusting method. The large view field off-axis three-reflector system comprises a main mirror, a secondary mirror, an aperture diaphragm, a third mirror and a focal plane. The main mirror is an off-axis hyperboloid reflector; the secondary mirror is a protruding spherical surface reflection mirror; the third mirror is an off-axis secondary recessed flat spherical mirror; the master axes of the master mirror and the third mirror are superposed as a reference axis; the aperture diaphragm is successively arranged on the secondary mirror; the optical axis of the secondary mirror is superposed with the master axis of the third mirror; a target light ray from infinity enters the secondary mirror after reflection of the main mirror and enters the third mirror through the reflection of the secondary mirror; and then the light ray is imaged on the focal surface. The invention solves the contradiction between the large view field off-axis three-reflector system, the processing and adjusting. The large view field off-axis three-reflector system adopts a simple structure and can realize the wide width imaging, wherein the effective view field reaches 12 degree*3.5 degree.