Electrocatalytic hydrodechlorination (ECH) is an efficient method for dechlorination of chlorinated organic pollutants. Preparation of working electrode used in ECH is of great importance. Dopant ions doped in polypyrrole had effects on Pd/PPY/Ni composite electrode. The influences of dopant ions on morphology and ECH performance of composite electrode were investigated. The removal rates of 2,4-DCP for Pd/PPY(PTS)/Ni electrode reached 91.1％, higher than others, especially than that of Pd/PPY(NaClO₄)/Ni. The effects of strongly adsorbed anions (ClO₄-, Cl-) in catholyte on electrochemical hydrodechlorination activity of the composite electrode via removal of 2,4-DCP were studied. 