The purposes of this study were to analyze the optimal process parameters of the atmospheric plasma and pen-like plasma by using a Taguchi method. Polyester fabrics improved the hydrophilic characteristic after the plasma-surface modification. Spin coating was used to apply uniform thin layers of polyaniline, poly (3,4-ethylenedioxythiophene) or graphite onto polyester fabrics, and then the sheet resistance measurement and the electromagnetic interference shielding effectiveness test were evaluated. From the results of Taguchi experimental and variance analysis, the optimal process parameters combination was applied to coated graphite on polyester fabric. The electromagnetic interference shielding effect of polyester fabrics was improved and the desired sheet resistance was also maintained.