The invention provides a tool for machining spherical surface pads. The tool is used for using a vertical lathe to machine arc surfaces of the spherical surface pads and comprises a base and lining plates, wherein the base is cylindrical, a first groove is formed in the outer wall of the base in the axial direction, the lining plates are arranged in the first groove, and threaded holes for connecting the spherical surface pads are formed in the lining plates. Multiple spherical surface pads can be fixed on the tool for machining the spherical surface pads, the vertical lathe is utilized to rotatably machine the arc surfaces of the spherical surface pads on the tool, the machined arc surfaces have the same radius, and then redundant portions are milled off according to the different requirements for length and width. If spherical surface pads different in radius are needed to be machine, the same tool can be still used, and the required portions can be cut after arc surface machining is completed.