Abstract: Provided by the present invention relates to the field of optical technology and is a symmetric imaging plane free-form surface optical system having a two-dimensional large field of view comprising a first reflector, a second reflector, a third reflector, a fourth reflector and a detector imaging plane which are arranged along a light path direction in sequence, and further comprising an aperture stop, wherein a position wherein the aperture stop is located at is overlapped with a position wherein the second reflector is located at such that a light beam is allowed to be reflected by the first reflector to the second reflector, after reflected by the second reflector then is injected to the third reflector, after reflected by the third reflector then is injected to the fourth reflector, after reflected by the fourth reflector then is injected to the imaging surface of the detector for imaging.