The invention relates to visual inspection, in particular to a manufacturing method of a visual inspection defect library for practical training. The manufacturing method comprises the following steps: S1, photographing to obtain a defect image; S2, performing fft speed optimization; S3, processing the defect image through a Gaussian filter to obtain a Gaussian image; S4, taking a gray value; S5,performing iterative operation on the difference image; S6, performing fast Fourier transform on the image after the iterative operation; S7, performing inverse transformation on the picture after Fourier transformation; S8, performing threshold segmentation on the transformed image, and taking an extreme value to obtain segmented regions; S9, communicating regions, and selecting regions accordingto specified morphological characteristics; and S10, drawing a circle at the defect part of the area, and calculating the central position of the area. According to the manufacturing method of the visual inspection defect library for practical training provided by the invention, the defect library can be conveniently established for the defects of the workpiece, the universality is high, and practical training personnel can know the specific process.