First, the product specifications and dimensions shall be inspected according to the standard for PTFE lined pipes, and then the steel lined PTFE lining layer shall be tested: the pipes and pipe fittings shall be subjected to a hydrostatic test at 1.5 times the design pressure, and the PTFE lining layer shall be 100% inspected for integrity after the hydrostatic test. The leakage point inspection method shall be electric spark test, and the appearance of the coating shall be inspected for corrosion protection. The coating thickness shall be uniform. The inspection and test shall be carried out at the service temperature of - 20~200 ℃, service pressure ≤ 2.5Mpa, allowable negative pressure DN ≤ 250mm is -0.09Mpa, and DN>250mm is -0.08Mpa.