Changeable efficient protective tool

A cutting tool, comprising:

• a cutting tool handle;
• a cutting tool holder;
• and
• a blade unit;
• wherein the cutting tool handle and the cutting tool holder are assembled with the blade unit, the blade unit is composed of two protective plates and a plurality of thin thread arranged between the two protective plates, and the cutting tool holder has two arms removably fixed with the two protective plates, respectively, the two arms of the cutting tool holder together forming a first plane, the two protective plates being parallel to each other and each having an outside surface, the first plane being perpendicular to the outside surface, wherein the two protective plates each has an upper portion, each of the two protective plates has a protrusion block formed on the outside surface thereof, the protrusion block has a slot formed therein, a lower portion of each of the two arms of the cutting tool holder has a bottom bar and an upper bar, the bottom bar is formed on the bottom of each of the arm of the cutting tool holder, the upper bar is longer than the bottom bar, the upper bar has a middle portion connected to the arm of the cutting tool holder, the bottom bar has a middle portion connected to the bottom of the arm of the cutting tool holder, the bottom bar and the upper bar are parallel to each other and both are perpendicular to the arm, thus the upper bar, the bottom bar and the arm form a ±shape, the upper bar has a facing down opening slot, when the cutting tool holder is fixed with the protective plates, each upper portion of the protective plates is slidely inserted into a corresponding facing down opening slot of the upper bar, and each bottom bar of the cutting tool holder is inserted into a corresponding slot in the protrusion block.