Polyester fabrics were coated by polyaniline synthesized via in-situ chemical polymerization and doped with HCl and H₃PO₄. The coated fabrics were examined by scanning electron microscopy, infrared spectrum and thermogravimetric analysis. The performance of flame retardancy and conductivity of polyester fabrics were studied by Limiting Oxygen Index (LOI) and cyclic voltammetry measurements. Experimental results indicated that the modified polyester fabrics had both excellent flame retardancy and conductivity. The sample molar ratio of ammonium persulfate (APS) to aniline of 1.2:1 resulted in the highest conductivity of 17.8 s/cm and the highest LOI of 42 vol% was acquired at the molar ratio of aniline to APS of 1:2.