Abstract: In view of the characteristics of fast speed, high sensitivity and non-contact of eddy current testing in metal crack defect detection, a detection method based on induced eddy current magnetic field was proposed, which aimed to achieve accurate and quantitative detection of crack defects in non-ferromagnetic metal components. The simulation was used to construct a model to simulate the eddy current distribution changes of different crack features in the alternating magnetic field, and reveal the specific influence of cracks on the magnetic field. At the same time, a test platform was built, and a detection device including an excitation signal generator, a detection probe, a signal processing system and a moving structure was designed to detect aluminum alloy specimens with different cracks. The simulation and experimental results showed that the designed detection probe based on induced eddy current magnetic field could quantitatively detect the crack length and depth.