PC/ABS alloy filled with 11 ${mu}{ extrm}{m}$ diameter stainless steel fibers was prepared with melt blending and compression molding. Volume resistivity, EMI shielding effectiveness, aspect ratio distribution, and configurations of SSF were investigated at various volume fractions and screw speeds on compounding. A dramatic change in volume resistivity was found at volume fraction of SSF in the range of 0.11％ to 0.34％ at which basic form of network was established in the matrix, while the percolation threshold of shielding effectiveness was observed in the range of 0.34％ to 0.57％. The composites prepared at screw speed of 20 rpm showed lower volume resistivity and higher shielding effectiveness than those prepared at 30, 40 rpm. An additional increase of volume fraction exhibited an overlapping of SSF and decrease of average distance among SSF but the volume resistivity and shielding effectiveness of composites changed slightly after percolation threshold.