In this paper, the effects of carbon black (CB) mass fraction on volume resistivity and electromagnetic shielding effectiveness (SE) of CB/Acrylonitrile Butadiene Styrene (ABS) composites were studied. The results indicated that when CB mass fraction was over 15 wt%, the volume resistivity dropped sharply and when it rose to 35 wt%, the volume resistivity achieved the lowest value about 103Ω·cm. In addition, there are two obvious percolation effect at 15~20 wt% and 25~35 wt% CB respectively in the course of the volume resistivity changing. Titanate coupling agent could greatly improve conduction and SE of CB/ABS composites. Lastly, the SE of CB/ABS composites was investigated by experimental observation.