Focusing on the current online inspection of PCB assembly process, traditional image inspection methods cannot extract high-level image features and high noise sensitivity. Our purpose is to use the semantic segmentation method to extract the high-level semantic features of PCB assembly images, realize the outline segmentation and identification of components, and explore an innovative PCB component detection method. The implementation method is to improve Deeplab v3+ by adding attention mechanism and multi-scale input channels, and improve the edge segmentation accuracy of the original network when facing large-scale images under industrial cameras. In the experiments, the improved network in this paper has achieved 88.19% mIOU on the data set, and the segmentation accuracy of PCB components is significantly better than that of traditional FCN. Compared with the original Deeplab v3+, it has increased by 6%, and can be applied to the segmentation and recognition of components in the PCB assembly process.