Abstract: To address the issue of punch shank rotation during the fastening process when using an inclined pin in vertical die Parting Horizontal forging machines. From a structural perspective, the relationships among the bevel angle of the Punch shank, the bevel angle of the inclined pin, and the resulting rotation angle are analyzed, and the calculation formula for the rotation angle is derived. This formula is applicable to the design of upset forging dies for non-rotational symmetric parts. Using this formula, the compensation angle for punch shank rotation can be conveniently calculated. Additionally, the angular tolerances of the inclined pin and punch shank bevel during manufacturing can be rationally determined based on the size of the forging section. The formula also aids in analyzing the impact of fastening bevel wear on forging mismatch during long-term use, thereby supporting die life management, Furthermore, an improved punch shank fastening method is proposed. Its key feature is the replacement of traditional inclined pins or set screws with compression pins, while the punch shank still employs a bevel for secure fastening. Positioning between the punch holder, punch shank, and punch is achieved using keys and pins, ensuring no rotation of the punch shank during tightening. The improved method offers advantages such as rapid assembly/disassembly, the die design is simple, and extended service life of both the punch shank and compression pins.