A lithography pupil shaping optical system, comprising: an illumination mode generation unit, a rotatable wave plate, a polarization beam splitter unit, a ring I generation unit and a ring II generation unit; wherein said illumination mode generation unit comprises a diffractive optical element and a zoom collimating lens group, wherein the diffractive optical element is exchangeable to achieve conventional, dipole, and quadruple illumination modes, respectively, said ring I generation unit comprises a first quarter-wave plate, a first convex axicon and a first movable mirror, said ring II generation unit comprises a second quarter-wave plate, a second convex axicon and a second movable mirror, and wherein the above components are arranged as follows: the diffractive optical element, the zoom collimating lens group, the rotatable wave plate, the polarization beam splitter unit, the first quarter-wave plate, the first convex axicon and the first movable mirror are placed sequentially along the positive direction of z-axis; wherein the conical tip of said first convex axicon is faced with said first movable mirror, said first movable mirror is coated with a polarization-maintaining reflection film, said first movable mirror comprises mechanical structures for continuously adjusting the distance between the conical tip of said first convex axicon and said first movable mirror; the lithography pupil shaping optical system is configured such that light passing through said polarization beam splitter unit is split into reflected light and transmitted light; and along the direction of reflected light, said second quarter-wave plate, said second convex axicon and said second movable mirror are placed sequentially; the conical tip of said second convex axicon is faced with said second movable mirror, said second movable mirror is coated with a polarization-maintaining reflection film, said second movable mirror comprises mechanical structures for continuously adjusting the distance between the conical tip of said second convex axicon and said second movable mirror; and the rear surface of said diffractive optical element is placed at the front focal plane of said zoom collimating lens group. the diffractive optical element is exchangeable to achieve conventional, dipole, and quadruple illumination modes, respectively, said ring I generation unit comprises a first quarter-wave plate, a first convex axicon and a first movable mirror, said ring II generation unit comprises a second quarter-wave plate, a second convex axicon and a second movable mirror, and wherein the above components are arranged as follows: the diffractive optical element, the zoom collimating lens group, the rotatable wave plate, the polarization beam splitter unit, the first quarter-wave plate, the first convex axicon and the first movable mirror are placed sequentially along the positive direction of z-axis; wherein the conical tip of said first convex axicon is faced with said first movable mirror, said first movable mirror is coated with a polarization-maintaining reflection film, said first movable mirror comprises mechanical structures for continuously adjusting the distance between the conical tip of said first convex axicon and said first movable mirror; the lithography pupil shaping optical system is configured such that light passing through said polarization beam splitter unit is split into reflected light and transmitted light; and along the direction of reflected light, said second quarter-wave plate, said second convex axicon and said second movable mirror are placed sequentially; the conical tip of said second convex axicon is faced with said second movable mirror, said second movable mirror is coated with a polarization-maintaining reflection film, said second movable mirror comprises mechanical structures for continuously adjusting the distance between the conical tip of said second convex axicon and said second movable mirror; and the rear surface of said diffractive optical element is placed at the front focal plane of said zoom collimating lens group. the diffractive optical element, the zoom collimating lens group, the rotatable wave plate, the polarization beam splitter unit, the first quarter-wave plate, the first convex axicon and the first movable mirror are placed sequentially along the positive direction of z-axis; wherein the conical tip of said first convex axicon is faced with said first movable mirror, said first movable mirror is coated with a polarization-maintaining reflection film, said first movable mirror comprises mechanical structures for continuously adjusting the distance between the conical tip of said first convex axicon and said first movable mirror; the lithography pupil shaping optical system is configured such that light passing through said polarization beam splitter unit is split into reflected light and transmitted light; and along the direction of reflected light, said second quarter-wave plate, said second convex axicon and said second movable mirror are placed sequentially; the conical tip of said second convex axicon is faced with said second movable mirror, said second movable mirror is coated with a polarization-maintaining reflection film, said second movable mirror comprises mechanical structures for continuously adjusting the distance between the conical tip of said second convex axicon and said second movable mirror; and the rear surface of said diffractive optical element is placed at the front focal plane of said zoom collimating lens group.