Pressure vessels are extensively applied as a kind of equipment that plays an important role in many industries relating to national economy such as petrochemical industry, energy industry, scientific research and military industry. Pressure vessels are easily exploded and burned, therefore endangering the safety of personnel, equipment and properties and causing environmental pollution accidents due to sealing, bearing, medium and other causes. At present, China has listed pressure vessel as an important product that requires supervision and inspection. Supervision, inspection and technical examination of pressure vessel are performed by the institution designated by China in accordance with the national regulations and standards.