Abstract: Pd/Ti electrode was prepared on Ti substrate electrode in hydrochloric acid containing PdCl2 using cyclic voltammetry. The electrocatalytic performance toward electrochemical reduction reactivity of 2,4-dichlorobenzoic acid (2,4-DCBA) on Cu, Ag, Ti and Pd/Ti was investigated. Compared with Cu, Ag and Ti electrodes, Pd/Ti electrode exhibited a high electrochemical activity for the reduction process of 2,4-DCBA in NaOH solution. In situ FTIR was applied to analyze the electrochemical dechlorination mechanism of 2,4-DCBA systematically. The results showed that 2,4-DCBA was electroreduced to its free radical ion after receiving an electron. Then the 2,4-DCBA free radical took off two chloride ions and produced the benzoic acid free radical. After receiving another two electrons and two protons, the final product benzoic acid was obtained.