Valve is the control part of fluid transportation system, which has the functions of cut-off, regulation, diversion, prevention of countercurrent, stabilization, diversion or overflow. The valves used in the fluid control system, from the simplest stop valve to the various valves used in the extremely complex automatic control system, have many varieties and specifications. The valve can be used to control the flow of air, water, steam, various corrosive media, mud, oil, liquid metal and radioactive media. Valve testing is for valves (1) material inspection (composition, tensile, impact, hardness, corrosion test, gold equivalent); (2) appearance inspection (internal and external flatness, smoothness, etc.); (3) dimensional inspection (parallelism, dimensional tolerance, etc.); (4) structure inspection (check the state of valve assembly and function, etc.); (5) pressure inspection (pressure resistance inspection, air tightness inspection and leakage inspection of valve body); (6) non destructive test (penetrant test, radiographic test, etc.); (7) leakage test (API 622 leakage, API 624 methane low leakage, etc.); (8) other tests.