Manual work is easy to fatigue, unstable, difficult to control, high cost, and with the improvement of manufacturing quality requirements, AOI instead of labor has become the choice of more and more enterprises. AOI grabs board images in real time through high-precision color industrial cameras, adopts convolutional neural network algorithm to process images, intelligently determines defective components and solder joints, and effectively controls quality. With the development of smt patch processing industry, the stronger the function, the mounted zero device accuracy is getting higher and higher, the volume is getting smaller and smaller, the human visual inspection ability is far from enough, AOI instead of labor, with higher stability, repeatability and higher accuracy.