Abstract: The bending cracks of intergranular corrosion specimens of stainless steel weldments and castings were analyzed by metallographic microscope( OM),scanning electron microscopy( SEM) and transmission electron microscopy( TEM),and the results were compared with that of electrochemical potentiokinetic reactivation( EPR).The different microscopic characteristics between the crack arising from intergranular corrosion and mechanical damages were proposed,and then the distinction between the two methods was summarized.Combined with the method of GB 4334“Method of copper sulfate-sulfuric acid test for stainless steel”,the result evaluation method of intergranular corrosion for the stainless steel weldments and castings were improved.