Abstract: The middle and small-size diameter tube seats on the pressure-equipment are prone to damage, but due to its complex structure, only surface inspections are performed and it is difficult to satisfy the safety of the operation. By summarizing the structure of the headers on the pressure pipeline, the feasibility of ultrasonic test for different types of sockets is analyzed, and the coverage of the ultrasonic test and defects that may be missed is discussed for sockets that can be inspected. The reliability of pipe pedestal detection is realized by adding multiple detection methods. An accurate and simple positioning calculation method for detecting the flaw echo made the main pipeline inspection easy to implement. Through a large number of tube seat detection tests and socket anatomy, it is proven that the test results can meet the safe operation requirements of the fillet weld of the seat.