Abstract: Rubber content in acrylonitrile butadiene styrene resin (ABS) copolymerized with maleic anhydride (MAH) by bulk (MABS) and by emulsion polymerization (ABS1) was determined via 1H NMR. The MAH content in MABS was measured by means of end group analysis. Without the addition of any compatibilizers, MABS and ABS1 were blended with polycabonate (PC) respectively. Mechanical properties of the alloys were compared. The correlation between microstructure and properties was investigated via SEM and DMA. PC/ABS1 had higher impact and bending strength. The results indicated that PC/ABS1 had better compatibility and thus higher impact and bending strength than PC/MABS. Mechanical properties of PC/ABS alloy can be improved by increasing the contents of rubber and acrylonitrile.