Eddy current testing is now a widely used Non Destructive Test (NDT) method for determining the size of cracks in metallic structures. The probability of detection (POD) is a key metric in assessing the effectiveness of nondestructive evaluation techniques. The POD analysis using common method is studied and modified. The eddy current sensor effective is discussed to support the proposed method. The new method is shown better result in improve the POD than the common one. The estimates of POD as a function of crack size will be valuable for future model-assisted POD study.