The invention discloses a consumable material pretreatment mechanism applied to 3D printers. The consumable material pretreatment mechanism comprises a 3D printer shell, a first groove, a second groove, a spring, a transverse adjusting mechanism, a 3D printing head, a feeding cylinder, a stepping motor, a feeding hopper and a servo motor, wherein the 3D printer shell is characterized in that a connecting lug is fixed to the bottom of the side, a movable rod is connected with the inner side of the connecting lug in a manner of sliding up and down, a limiting block is fixed at the top end of the movable rod, a foot pad is fixed to the bottom end of the movable rod, and a limiting groove is formed in the connecting lug. According to the consumable material pretreatment mechanism applied to the 3D printers, a spiral feeding manner is adopted; the defect that continuous feeding cannot be achieved through a piston type pressurization manner is overcome; the production efficiency is improved; only the material body in a heating cylinder is heated instead of heating the whole stored material; the situation that the waste is caused when the molten material body is not used up is avoided; the raw materials are saved; meanwhile, the whole stored material does not need to be heated, so that the heating work can be reduced, and the energy consumption is reduced.