The invention discloses a fixture special for grinding and machining of an HSK (Hohl Schaft Kegel) shank series cutter. The fixture comprises a flange connected with a machine tool spindle, and an HSK adjusting mechanism, wherein the HSK adjusting mechanism comprises a convex block, the convex block is provided with cavities along a central axis; the cavity on the left side of the convex block isprovided with an HSK broach claw, and the cavity facing the right end surface of a bottom block is in a taper shape adaptive to an HSK shank; the flange comprises a flange plate and a connecting shaft horizontally and fixedly arranged on the left side of the flange plate, the right end surface of the flange plate is provided with a concave cavity, and the convex part of the convex block is positioned in the concave cavity; the left end surface of the bottom block is opposite to the right end surface of the flange; the flange plate at the circumference of the convex part is provided with a radial adjusting top thread, and the bottom end of the radial adjusting top thread leans against the external surface of the convex part; and the bottom block of the convex block is provided with an axial adjusting top thread, and the bottom end of the axial adjusting top thread leans against the right end surface of the flange. The fixture can effectively increase the combined rigidity of the shank to the machine tool spindle, greatly increase the repeated positioning accuracy and has a good high-speed locking property.