Abstract: The technical examination of the nondestructive testing of the LNG railway tank car found that the ultrasonic testing technology for the butt weld of the middle beam is not clear, the ultrasonic testing of the outer ring joint of the outer tank has a blind area, and the girth weld structure of the tri-through pipe joint is difficult to detect by RT, and so on. According to the feedback, the designers have modified or supplemented the technical requirements of NDT, which meet the requirements of the national regulations and standards of the relevant products and improve the technology of NDT.