The invention belongs to the technical field of nuclear reactor devices, and particularly relates to a sorting unit for different sizes of spherical elements of a high-temperature gas cooled reactor of a pebble bed. The spherical element sorting unit comprises a box, a rotor, a lining plate, a first detecting pore plate, a sphere feeding tube and a first sphere discharging tube; the box is provided with a sphere feeding channel and a first sphere discharging channel which are communicated with the sphere feeding tube and the sphere discharging tube directly; a shifting plate is arranged on the rotor; the first detecting pore plate comprises a first pore channel and a second pore channel; the shifting plate and the two pore channels of the first detecting pore plate are all provided with guiding inclined surfaces; and the size of the first pore channel is smaller than that of a large sphere and larger than the sizes of a small sphere and a medium-sized sphere. The detecting pore plate is used for blocking the large spheres and qualified fuel spheres in the margin of tolerance, the rotor drives the shifting plate to rotate so as to push fuel elements blocked by the detecting pore plate, the large spheres, the qualified spheres and the small spheres are discharged through three sphere discharging channels respectively, so that the spherical element sorting efficiency and accuracy can be improved, and the sphere blocking phenomenon in the sorting process can be eliminated due to the arranged shifting plate.