Abstract: In surface mounted technology(SMT) solder paste deposition automatic vision inspection, statistical pattern establishment takes long time and direct image segmentation suffers bad accuracy. However, the required position and height information can be extracted from the pads on the printed circuit board(PCB) and the stencil which is for solder paste deposition. The segmented images can be obtained by contrasting to the bared PCB images. Morphological processing can eliminate the tolerance between two same PCBs. Comparisons on experiment results showed this approach efficiently improved inspecting accuracy and speed.