Abstract: The slow strain rate tensile test of 304L stainless steel cladding for nuclear power was carried out, and the fracture of the sample was observed by scanning electron microscope. The results show that the stress corrosion cracking sensitivity coefficient of 304L stainless steel cladding for nuclear power was close to 1, and the macroscopic morphology of the fracture after testing in high temperature nitrogen, high temperature and high pressure water was basically the same, showing ductile fracture characteristics. The stress corrosion sensitivity of 304L stainless steel cladding for nuclear power was low in high temperature and high pressure water.