The elliptical head is a pressure part often used in pressure vessels. Under the working condition of internal pressure, the stress distribution of the elliptical head is more complicated, and the stress state is not as good as that of the spherical head. However, due to the convenience of manufacturing, the elliptical head is commonly used in medium and low pressure vessels. When designing pressure vessels, it is often necessary to open holes on the elliptical head, which makes the stress distribution of the entire elliptical head more complicated. The finite element analysis method is now used to quantitatively analyze the structural stress of the elliptical head after opening, and to study the stress distribution of the elliptical head with large openings, providing theoretical analysis data for engineering design.