Indexable milling insert and milling tool thereof

The invention relates to the technical field of cutter design, and discloses an indexable milling blade, which comprises a first cutting part and a second cutting part which are distributed in the length direction of the milling blade and have the same outline, the first cutting part comprises two main positioning surfaces which are distributed perpendicular to the thickness direction of the milling blade; a dislocation structure with offset in the direction perpendicular to the main positioning surface is arranged at the joint of the first cutting part and the second cutting part; the dislocation structure comprises a first axial positioning surface positioned on the first cutting part and a second axial positioning surface positioned on the second cutting part; after the second cutting part rotates around the center of the dislocation structure by 180 degrees, the projection coincides with the first cutting part; the first cutting part comprises two centrosymmetric cutting units, and each cutting unit compr