Abstract: Eddy current examination of the steam generator tubes was critical to the safe and economical operation of power stations. The most defect forms of the steam generator tubes are degradation and more frequmtly encountered defects are volumetrically small ones. In RSEM, it requires that 1 mm3 volume can be detected. The examination capability is researched in this paper. Through analysis of result data, the examination capability can meet the requirement of international standard.