The invention discloses a manufacturing method of a pattern ring of a segmented mold of a radial tyre. The manufacturing method comprises the following steps of: performing a CAD design on the pattern ring, establishing a 3D model of the pattern ring, then dividing the 3D model into corresponding single pattern blocks according to requirements, and simultaneously customizing a pattern ring blank,finishing preliminary works such as rough machining, heat treatment, reference plane machining and the like of the pattern ring; configuring a plurality of machine tools and completing the preparation work before production; establishing part processing cutter tracks required by each machine tool, generating semi-finishing, finishing and corner cleaning procedures of each pattern block according to the configured condition of the machine tools, and establishing a procedure list; executing the processing procedures according to a procedure list sequence; and assembling and debugging the plurality of processed pattern blocks. The manufacturing method has the advantages of simple process, difficult generation of thermal deformation on a workpiece during production, short production cycle, high production efficiency and high accuracy, and ensures the assembly accuracy of the a tyre mold.