Shielding ruler capable of conveniently adjusting horizontal extension and retraction and angle for cutting machine tool

The invention relates to a shielding ruler capable of conveniently adjusting the horizontal extension and retraction and angle for a cutting machine tool. The shielding ruler comprises an adjustment mechanism, a locking mechanism and an auxiliary mechanism, the auxiliary mechanism comprises a supporting plate, a hoop fixed to the supporting plate and a positioning rod cooperatively and slidingly inserted in the hoop, the adjustment mechanism comprises a baffle, two length scale rods, an angle dial and a connection rod, the ends of the two length scale rods are hinged to the two ends of the baffle respectively, the other ends of the two length scale rods are hinged to the two ends of the connection rod respectively, the end, parallel to the length scale rods, of the positioning rod is hinged to the middle of the baffle, and the locking mechanism comprises a bolt and a nut; the bolt penetrates through a long hole extending in the supporting plate in the front-back direction, the center of the angle dial and the