In this study the effects of adding GO and the change of ABS phase content on the physical properties of immiscible polycarbonate (PC)/poly(acrylonitrile-butadiene-styrene) (ABS) blends were discussed. The PC-GO/ABS composites were fabricated by using a twin screw extruder as two steps. PC/ABS blends were set at the weight ratios of 70/30, 50/50, and 30/70. First of all PC/GO composite was fabricated at 260 degrees C. And then the PC-GO/ABS composites were manufactured by using an extruder at 240 degrees C. The GO of 0.5 Wt% was inserted by PC/GO composite for all samples. It was confirmed by SEM and TEM that the ABS phase structures were changed from sea-island to inverse sea-island with increasing ABS content. The izod impact strength increased with adding GO when the contents of ABS were 30 and 50 wt%. It is interpreted by the reinforced ABS phase and compatibilizing effect of GO at the interface between PC and ABS. In the TEM images, most GO were located in the interface and ABS phase. GO location was checked indirectly by shear thinning effect and storage modulus of PC-GO/ABS composites.