Abstract: The transverse fatigue crack on the external surface of the hollow axle of EMU wasa typical hazard defect. If it is not detected in time, it may cause axle breaking accident. In this paper, an eddy current array inspection method wasproposed, which can effectively detect 0. 3 mm deep artificial crack under the condition of lacquer coating with 0. 3 mm thickness, and the detection ability wasbetter than the 1 mm deep groove equivalent of the existing ultrasonic flaw detection. This method can be integrated into the existing EMU axle flaw detection process, and used for the review of suspected defects in ultrasonic flaw detection, which have strong practical value.