Array eddy current sensor has the advantage of high speed scanning to wide area of conductive materials.Defects with different orientations have different effect on mutual inductance between array eddy current sensors.Thus more defect information can be obtained by measuring the mutual inductance.Transverse and longitudinal cracks are studied with 3-D finite element method based on ANSYS.The induced EMF amplitude of each coil is acquired corresponding to a given position of the crack.The simulation results show that the mutual inductance between array eddy current sensors can provide some useful information about characters of the cracks such as sizes and positions.