Abstract: The application of ultrasonic testing technology in the nuclear equipment testing of nuclear power plants is expounded. The main applications of the ultrasonic testing equipment include nuclear reactor seam welds and takeover welds, reactor pressure vessel main bolts, fuel assemblies, control rod assemblies, steam generator barrel welding and take over welds, pressure vessel barrel welds, steam generator/stabilizer manhole bolts, main pump welds, main pipe welds, nuclear auxiliary pipe welds and steam turbine blades. The defect height measurement and ability verification method of ultrasonic inspection technology is also described.