The invention discloses a synchronizer gear ring inner ring machining composite clamp which comprises a connection disc, a disc body, a floating supporting disc, a floating spherical pull rod, a mainshaft pull rod, a supporting disc limiting block, a workpiece pull rod, an anti-rotation pin, a pressing plate, a clamp base, an axial positioning block, a pressing spring, a floating positioning bodyand other components. The connection disc is connected with the disc body, the floating supporting disc and the workpiece pull rod are arranged in the disc body, the anti-rotation pin is installed outside the disc body and abuts against the outer surface of the workpiece pull rod, the floating supporting disc is installed on the floating spherical pull rod through the supporting disc limiting block, and the floating spherical pull rod is connected with the main shaft pull rod on a machine tool. A floating type pulling finger-shaped clamping disc and a floating self-centering clamp are adopted, axial pressing force acts on the product end face, it is ensured that synchronizer inner ring product key important characters meet client drawing quality requirements, a machined synchronizer gearring product is reliable in quality, and automatic feeding and discharging requirements can be met.