Abstract: Two commonly used austenite steel grain size displaying methods-the grain boundary corrosionmethod and oxidizing method were compared and studied by comparison method and cut-point method with differentkinds of steels as examples under different heating condition.The results show that the austenite grain displayed byoxidizing method could meet the accuracy requirement for production testing,and the difference of austenite grainmean chord length displayed by oxidizing method and grain boundary corrosion method would be affected by the steelkinds and heating temperature.