Abstract: The equipment gate of AP1000 nuclear power unit is a necessary passage for large scale equipment to enter or exit the nuclear island. However, the blunt edge position of the stiffening plate in equipment gate of this unit is sometimes out of tolerance after soldering, and part of the weld width is over wide and the thickness ratio is too large, even beyond the X-ray machine maximum transmission thickness. It caused great difficulty for radiographic testing. In this paper, the scheme of radiographic testing in this special case is discussed, and by measuring the width and thickness of weld on site, a solid model of weld seam was established and the best scheme of radiographic testing for weld seam in the stiffening plate of equipment gate was formulated. The test was carried out and a better effect was therefore obtained.