The invention relates to the manufacturing technique of nuclear fusion devices and particularly discloses a manufacturing method of a complex curved surface of a large-scale Tokamak vacuum chamber shell. The manufacturing method comprises the steps: after a curved surface is expanded for discharging, carrying out cold-pressing pre-bending, heating a blank before hot-pressing, carrying out solutiontreatment after hot-pressing formation, and carrying out reformation, so as to obtain a target product. According to the method, by reasonably designing the whole craft process, the finally manufactured curved surface can stably reach relatively good shape and dimension precision; by carrying out solution treatment and controlling the formation temperature of the secondary formation process, thefinal delivery state of the curved surface is a solid solution state, the residual stress produced in the formation process is reduced, the mechanical and physical properties of the curved surface areeffectively restored to the states of an original plate, the material defects are avoided, and the curved surface does not have intergranular corrosion trend; and by controlling the heating temperature and time in each procedure, compared with the original plate, the degradation of the grain size grade of the final curved surface is below level 1, and the grain size of the curved surface can meetthe use requirements.