Abstract: The electrocatalytic activity of Ti/PbO₂ anode for degradation of p-nitrophenol was studied with linear sweeping voltammetry and galvanostatic electrolysis.The electrocatalytic degradation pathway of p-nitrophenol was explored by HPLC analysis of the reaction mixture in the anodic oxidation and cathodic reduction processes.The results indicate that Ti/PbO₂ electrode can electrocatalyze the degradation of p-nitrophenol effectively.The conversion of the 1.0 mmol/L p-nitrophenol achieved 98.6% when the electrolysis was carried out for 240 min with a constant current of 40&×10^-3 A/cm² at 35℃.The pathway of the electrocatalytic oxidation degradation of p-nitrophenol is p-nitrophenol→hydroquinone and pyocatechol→benzoquinone→maleic acid→oxalic acid→CO₂ and H₂O.The main product of the first step is hydroquinone.The conversions of benzoquinone to maleic acid and maleic acid to oxalic acid are the rate determining steps of anodic oxidation process.The p-nitrophenol can be reduced at the cathode.The reduction products include p-aminophenol.In an electrolytic cell without diaphragm,the cathodic reduction product,p-aminophenol,can be oxidated easily at the anode.The synergsic effect of the cathode and anode speeds up the degradation of p-nitrophenol in an undivided electrolytic cell compared to an electrolytic cell with diaphragm.