Abstract: Compared with 2nd generation nuclear major equipment, the non-destructive technique for 3rd generation nuclear equipment has its uniqueness because of the complex structure of the latter. Through introduction of typical case studies of quality problem during ultrasonic test (UT) of steam generator, this paper reveals and analyzes the difficulties of UT technique during the 3rd generation equipment manufacturing, and searches for the UT methods and relevant solutions in manufacturing which is in compliance with the NDE standards of 3rd generation equipment manufacturing.