Abstract: The susceptibility of AISI 304L austenitic stainless steel to intergranular attack mainly caused by the Cr-depletion in grain boundaries was detected by the square-wave potentiostatic pulse technique. The degree of the sensitization of 304L stainless steel can be exactly and quantitively illustrated by this technique.The maximum reactivation current density corresponding to 10th pulse,ir10,was selected as a characteristic parameter for the detection of sensitization.The degree of the sensitization determined by square-wave potentiostatic pulse technique was in agreement with those obtained from DL-EPR and ASTM standard tests.