This paper presents an electromagnetic testing method for the inspection of cracks in an overlay welding area. The overlay welding method is usually used to repair failure welds in a structure in which the components are difficult and expensive to replace. The inspection system uses an air-core exciting coil to produce an electromagnetic field in the overlay welding area and a linearly integrated giant magnetoresistance (GMR) sensor array (LIGiS) to measure the distribution of the electromagnetic field around the cracks; thus, the cracks can be inspected. The LIGiS is fabricated using 32 GMR sensor elements arrayed at 0.6 mm intervals. Artificial cracks with different sizes, orientations, and locations on the crisp surface of an overlay welding sample are tested to verify the effectiveness of the proposed method.