The invention discloses a winding and unwinding mechanism. The winding and unwinding mechanism comprises a support, a winding assembly and a reel positioning and supporting assembly. The winding assembly and the reel positioning and supporting assembly are both arranged on the support, and the positions of the winding assembly and the reel positioning and supporting assembly on the support are adjustable in the axial direction of winding and unwinding of a material reel. When material rolls are fed and discharged, the reel positioning and supporting assembly serves as an auxiliary mechanism for feeding and discharging operation, manual feeding and discharging or automatic feeding and discharging can be met, the fed and discharged material rolls are accurately positioned and supported, the feeding and discharging speed of the material rolls is increased, and the production efficiency is improved. And a reel clamp in the winding assembly can conveniently and accurately clamp or loosen a reel to accurately position, so that the production efficiency is improved, the winding and unwinding stability and uniformity of the coil stock are improved, and the quality of the coil stock is ensured. In addition, the winding and unwinding mechanism is wide in winding and unwinding applicability to material rolls with different widths and sizes.