Polycarbonate(PC)/ABS is a very common immiscible polymer blend The internal structure such as distribution of each component in the injection moldings of PC/ABS would be strongly affected by the processing parameters. Especially, the weld line formed by meeting two melt flows and the internal structure at the weld area would be a very complex form. By observing the etched samples of PC/ABS injection moldings using scanning electron microscopy, a weld part with fine dispersion of ABS was found in the area below V-notch. When tensile load was applied perpendicular to the weld line, the fracture initiated from the V-notch, but the crack propagated along the interface between the weld part with fine dispersion and the part behind the weld part. This leads to unique characteristics of the weld strength.