Abstract: With the development of national technology and economy, more and more thick wall products were produced, which could bear high temperature and high pressure such as heavy vessels and hydrogenation reactors. Stricter requirements were put forward to keep good quality of the products. Physical and chemical tests of large vessels should be carried out on construction site. Due to the simple facilities and changeable environment of the construction site, the quality control of physical and chemical tests was especially important. Only when each factor of physical and chemical tests on site was accurately controlled, the accurate data of physical and chemical tests on site could be obtained and accurate testing reports could be issued.