A poly L-leucine（L-LEU） modified single-walled carbon nanotube/glass carbon electrode（SWCNT/GCE） was fabricated by electrochemical polymerization method.The electrochemical behaviors of hydroquinone（HQ） and catechol（CC） on the modified electrode（poly L-LEU/SWCNT/GCE） were investigated by cyclic voltammetry（CV）,differential pulse voltammetry（DPV） and electrochemical impedance spectroscopy（EIS）.The experimental results suggested that poly L-LEU/SWCNT/GCE exhibited an obvious electrocatalytic activity and electroseparation.The redox responses of HQ and CC increased significantly,the differences of peak potential of oxidation and reduction were 124 mV and 131 mV,respectively.The linear response ranges for HQ and CC were 2.0×10-7-1.0×10-4 mol/L and 5.0×10-7-1.0×10-4 mol/L,with detection limits of 8.0×10-8 mol/L and 1.0×10-7 mol/L,respectively.The modified electrode showed a good repeatability and stability.The proposed method was applied in the determination of HQ and CC in simulated water samples with satisfactory results.