Bottleneck thread double-layer protection jig

A double-layer protection jig for bottle mouth threads relates to the field of bottle mouth jigs and comprises a jig shell, a first space with an opening is arranged in the jig shell, a third space is arranged on the outer side of the first space, and four second spaces are distributed on the inner side wall of the first space at equal intervals. An arc-shaped clamping block is slidably connected into each second space, a latex protection pad is fixedly arranged on the end face, close to the center line direction of the first space, of each arc-shaped clamping block, and a clamping sliding block is fixedly arranged on the end face, away from the center line direction of the first space, of each arc-shaped clamping block; during clamping, the latex protection pad abuts against the bottle opening, so that the protrusions on the surface of the latex protection pad elastically deform and are squeezed into threads of the bottle opening, the threads of the bottle opening can be effectively protected from being dama