A sensitive and selective method for the determination of ascorbic acid (AA) using [Cu(phen)2]2+/multiwalled carbon nanotubes modified glassy carbon electrode was developed. Electrochemical behavior and surface characteristics of the modified electrode were studied using scanning electrode microscopy (SEM), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The experimental results showed that the modified electrode enhanced the electrochemical response of AA and exhibited good analytical performance for AA determination from 10 to 1 042mmol/L with a low detection limit of 9.67μmol/L (S/N=3). The modified electrode was also applied to the determination of AA in the Vitamin tablets and showed good recovery.