Abstract: A poly (glutamic acid) modified carbon pasted electrode was prepared.The electrochemical behavior of K4Fe(CN)6/K3Fe(CN)6 at this modified electrode was investigated by using cyclic voltammetry (CV) and Ac impedance methods.The results indicated that the modified carbon pasted electrode can make the redox peak current of K4Fe(CN)6/K3Fe(CN)6 larger and impedance smaller.The determination of Cu2+ at poly (glutamic acid) modified carbon pasted electrode was taken by adsorptive voltammetric procedure.In the acetate buffer solution (pH 4.50),Cu2+ was accumulated on the electrode surface by cathodic reduction at -0.20 V (vs.Ag/AgCl ),then the Cu2+ has a DPV oxidation peak at the potential of 0.14 V.The peak current was linearly increased with the concentration of Cu2+ in the range of 1.57×10-8—1.57×10-5 mol/L,with a detection limit of 5.00×10-9 mol/L.The modified electrode can be used to determine Cu2+.