The polymer modified electrode was manufactured by a cyclic voltammetric method using a synthesized Ni(II) complex with dianionic benzoN4 macrocycle. The electrocatalytic characteristics for the oxidation of L-Dopa at a polymer modified electrode was studied by cyclic voltammetry. The results showed that the oxidation peak potential was shifted to the lower potential and the oxidation peak current was increased in comparison with the unmodified electrode. The optimal experimental conditions for the voltammetric determination of L-Dopa were as follows: pH, 7.4; temperature, 35 C; the number of scan for modification by cyclic voltammetry, 1; preconcentration time, 90s. The polymer modified electrode was stable to determine L-Dopa for more than 2 months. The calibration curve for L-Dopa that linear range is 6.0×10 M~4.0×10 M, the correlation coefficient is 0.996, and the detection limit is 9.0×10 M. The effects of interferences were studied for 27 candidates which might exist in biological samples all the species except dopamine did not interfere the determination of L-Dopa.