For the detection of surface cracks and hidden cracks in ferrite inductorthe traditional machine vision method has some problemssuch as fuzzy image and low recognition rate. an inductor crack detection method based on laser scanning thermal imaging technology is proposed. The thermal imager is used to capture the temperature change of the sample surfaceand the image is synthesized based on the second-order differential algorithm.The contour extraction algorithm is used to remove the interference of the peripheral contour and filter the uniform image with the second largest valueand the edge detection is used to extract the crack. Finallyusing the crack area and aspect ratio and hog features as input featuressupport vector machine is used for image recognition. The results show that all the cracks can be imaged correctlyand the correct rate of crack recognition is 98.5%which is better than other detection algorithms.