In this study, the effect of fabrication method on the basic properties and electromagnetic interference (EMI) shielding performance of the nylon66/carbon filler composites was discussed. The carbon fillers such as carbon black (CB), multi-walled carbon nanotube (MWCNT), and nickel coated carbon fiber (Ni-CF) were used. The master-batch (MB) of CB/MWCNT and feeding method of Ni-CF were used as fabrication methods. The concentration of CB and MWCNT in MB was fixed at 20 wt% and MBs were fabricated by using a twin screw extruder at die temperature of 280 °C. The composites were prepared with two different feeding methods that Ni-CFs were fed separately at main and side feeder. The improvements of melt flow and electrical properties were confirmed from complex viscosity and surface resistance in the case of nylon 66/CB/CNT/Ni-CF composites fabricated through MB, and EMI shielding performance increased largely when Ni-CF was fed into the composites at side feeder.