In the stamping process, the sealing mould of the traditional large pressure vessel is easy to wear out, which leads to the poor quality and short die life, so the production efficiency is affected seriously. A finite element model consisting with the actual stamping die of the large pressure vessel head was established by ABAQUS software. Then, the main factors of head die wear were analyzed, and material hardness, friction coefficient and clearance between punch and die of the traditional large pressure vessel head die were improved reasonably. The analysis results show that the die wear is the smallest with the hardness of the die material 75-85 HRC, the friction coefficient 0.06-0.12, and the convex die and the concave die gap 1.1-1.3 mm.