In order to improve the shear performance and service life of the oblique blade guillotine, the AlTiN coating was deposited on the edge of the tool by arc ion plating. The microstructures, nanomechanical properties and the shear properties of the coatings and were studied. The microstructure of AlTiN coating was analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD). It was found that the average thickness of coating was 3.9 μm, which was composed of CrN and AlTiN, and the surface of AlTiN coating was dense, and the composition of the coating phase are mainly hexagonal h-AlN, cubic c-AlN, TiN. The mechanical properties of AlTiN coating were studied by nanoindentation and scratching. The results showed that the nano-hardness of the coating was 33.207 GPa, which is 1.49 times that of the substrate. And the adhesion force reached 57.44 N. The shear test of electrical steel plate was carried out by using NC oblique blade guillotine machine. It was found that the shearing performance was improved obviously. The quality of shearing section of the electrical silicon steel sheet is improved. the cross section is relatively flat. The distribution of the characteristic band is uniform and the shear zone height increases significantly.