The invention relates to an automatic paper winding drum expansion and shrinkage mold device. A winding drum mold is connected with one end of a main shaft by a mold receiving tray and comprises a supporting tube, and circular discs concentric with the supporting tube are arranged at two ends of the supporting tube; a drum formed by multiple arc plates is arranged between the outer edges of the two circular discs; the drum comprises an arc fixing plate, two arc stretching plates and an arc movable wedge block; a stretching reset spring for driving the stretching plate to return is arranged between the arc stretching plate and the supporting tube, an inner cavity of the supporting tube is communicated with an inner cavity of the main shaft of a drum winding machine, a core shaft is arranged in the supporting tube, a pushing rod for pushing the core shaft to move is arranged in the main shaft, and is in transmission connection with a power device, a lifting guide rod is arranged between the core shaft and the movable wedge block, a transitional step unit is arranged on the core shaft, and comprises a small step and a large step in transitional connection with the small step; and one end of the core shaft props against the pushing rod and the other end of the core shaft is provided with a core shaft reset spring. According to the automatic paper winding drum expansion and shrinkage mold device, the diameter of the mold can be automatically controlled to be reduced and increased, the labor intensity is alleviated, the production efficiency is improved and the labor force is saved.