It is necessary to check the connection of printed circuit in PCB printing circuit manufacturing. Before the use of machine vision testing, this inspection relies mainly on the naked eye inspection. However, manual detection has many disadvantages. The PCB line is complex and small, because of the irresistible factors such as eyestrain,Some of the bad products will be missed. Moreover, the long time inspection affects the eyesight of the employees, resulting in the loss of the personnel in the second place. This problem is also a major problem that plagues many enterprises.