Abstract: Through-type eddy current probe calibration is indispensable to ensure the accuracy of on-line detection. In this paper, an eddy current probe calibration approach is studied of using contrast samples with standard artificial defects in it. According to standard depth of penetration of copper rods, the criteria of artificial defects are determined. In accordance with the speed of copper rods, through comparison of the corresponding standards for defect detection signals, the accurate calibration of probe is implemented. Experiments show the effectiveness of the method.