Abstract: As electronic components get smaller and the board densities become more compact, it is necessary for automatic inspection in electronic manufacturing.The automatic optical inspection(AOI) system is demanded more precise and intelligent.The traditional inspection methods require large quantity samples of all types to train the inspector, or do some complicated setting.To overcome the disadvantages, an intelligent method was proposed.Firstly, a series of features of soldered joints were defined.Then, an automatic boundary setting method based on statistic was introduced.Finally, the neural network was established to classify the soldered joints.The performance of the method was verified by the experiment.