The invention belongs to the technical field of communication, and specifically relates to a preparation device for a protection box of a communication cable joint, which includes a main body, a top plate, a groove, a pressing plate, a punch, a fixed shaft, a rotating rod, a supporting rod, a spring, a limit rod, Gear rod, first gear, second gear, ejector rod, die, fixed plate, electric push rod, push plate, water pipe and water pump. The invention forms a cavity by pressing the concave mold and the convex mold and then performs injection molding, which facilitates the preparation of the protective box, and facilitates the removal of the protective box from the mold while the top plate moves, which improves the convenience of operation and reduces the difficulty of operation. It is conducive to the ejection of the protection box; the preparation device of the communication cable joint protection box facilitates the support of the protection box through the movement of the support rod, and facilitates the unloading of the protection box and the unloading of the protection box through the movement of the push plate. materials, reducing the operating procedures, improving work efficiency, and improving the degree of integration.