The invention belongs to the technical field of nuclear fusion device manufacturing, and particularly relates to a solid solution treatment tool for a curved surface of a large tokamak vacuum chambershell. The solid solution treatment tool comprises a supporting main body and arc-shaped pressing plates, wherein a plurality of transverse supporting plates are positioned by mounting grooves which are machined in a middle longitudinal supporting plate in advance and then are welded into a whole with all the longitudinal supporting plates, a plurality of pairs of pressing plate clamps and reinforcing rib plates are correspondingly welded on the left longitudinal supporting plate and the right longitudinal supporting plate, U-shaped grooves are formed in the positions, opposite to the arc-shaped pressing plates, of each longitudinal supporting plate, a curved surface connecting transition plate is welded on the side surface of the middle of the supporting arc surface of the middle longitudinal supporting plate, and the left longitudinal supporting plate and the right longitudinal supporting plate each are provided with two pairs of lifting holes. According to the solid solution treatment tool for the curved surface of the large tokamak vacuum chamber shell, solid solution deformation of the curved surface of the large tokamak vacuum chamber shell can be effectively reduced, multiple times of repeated use can be achieved the severe condition of solid solution heat treatment, the structure is simple, manufacturing is convenient, and the production cost is saved.