Abstract: Poly(3,4-ethylenedioxythiophene)(PEDOT) was synthesized in lignosulfonic acid (LS) solution using sodium persulfate (Na₂S₂O₈) as an oxidant to prepare PEDOT/LS aqueous dispersion. The effects of LS and Na₂S₂O₈ weight ratio, pH value, solid content and temperature on PEDOT/LS particle size and conductivity were studied. The optimized polymerization conditions were found as follows: LS to EDOT weight ratio=2.0~2.5, Na₂S₂O₈ to EDOT molar ratio=1.3:1, pH=1.5, solid content percentage=1.8%~2.5% and temperature=10~20℃. The surface resistance of the prepared PEDOT/LS coating is lower than 10⁸ Ω·sq^-1, and the coating is smooth and transparent with 2ed-grade adhesion, which can be used as antistatic agents.