Abstract: Inter-granular corrosion sensitivity is one of the important test items of stainless steel. GB/T 4334-2020 has been issued and implemented the content of standard update was interpreted and analyzed. The new standard has made a series of changes in the name, sampling, preparation and sensitization system. The test methods have been greatly updated, including the abolition of nitric acid-hydrofluoric acid method, the addition of copper-copper sulfate-35% wt sulfuric acid method and 40% wt sulfuric acid-iron sulfate method. The use conditions and scope of various test methods have been clarified, and the test parameters of the bending evaluation method have been modified.