The invention provides a two-freedom-degree mechanical protection mechanism of a cutting-off cutter and a use method of the two-freedom-degree mechanical protection mechanism. The two-freedom-degree mechanical protection mechanism comprises a cutter, a connecting element, a protection device and a sliding device, wherein the protection device is fixedly connected with one end of the sliding device, the cutter is glidingly connected with the gliding device through the connecting element, and the protection device horizontally slides relative to the cutter through the gliding device. The two-freedom-degree mechanical protection mechanism concretely comprises a first screw nut, a first screw rod, a second screw nut, a second screw rod, a base, a cutter blade, a protecting sleeve, an elastic sheet, a slide block, a third screw nut, a first screw, a fourth screw, a second screw, a second spring, a second position limiting block, a first spring and a first position limiting block. The two-freedom-degree mechanical protection mechanism is provided with the two-freedom-degree cutter, the protection device adopts the one-hundred-percent mechanical structure, and the structure is simple and reliable; the automatic device based on an electronic device is not needed, and the use of electric circuits and motors is avoided; the operation is simple, and the operation action addition is not needed; the normal use of the cutter is not hindered by an automatic protection function of the cutter.