The invention provides a vertical shaft rotation type drawing mechanism for a forage grass cutting flatting mill. The vertical shaft rotation type drawing mechanism comprises a first horizontal shaft protecting cover, a first horizontal shaft, a bevel gear, a power input box, a rotation box, a vertical shaft, a second horizontal shaft, a connecting plate, a limiting box, a connecting frame, a cylindrical roller and a supporting frame. A tractor transmits power to the first horizontal shaft, the first horizontal shaft transmits power to the vertical shaft, the vertical shaft transmits power to the second horizontal shaft, the second horizontal shaft transmits power to the forage grass cutting flatting mill, and power transmission is finished. When the tractor makes a turn, a power transmission system works normally, the power input box and the limiting box make a turn together with the tractor, the power input box rotates around the vertical shaft with the axis of a round sleeve as the center, and the forage grass cutting flatting mill can be immobile at the original position. When the tractor continues to run after making a turn, the rotation box is subject to forward traction and pulls the forage grass cutting flatting mill to work. When the vertical shaft rotation type drawing mechanism is in work, the supporting frame is put away and locked at 0 degree; after the work is finished, the supporting frame is placed down to be locked at 90 degrees, and the forage grass cutting flatting mill is supported.