Abstract: To prepare mesoporous carbon modified glassy carbon electrode (GCE), a dispersion of mesoporous carbon in 5 g·L-1 chitosan solution was added dropwise onto the surface of GCE, and dried in oven. Electrochemical property of the modified electrodes was studied by cyclic voltammetry. It was found that a pair of sensitive oxidation and reduction peaks given by p-benzenediol was observed at the modified electrode and that the peak current was enhanced obviously as compared with the bare GCE. Based on these findings, a selective method for determination of p-benzenediol by cyclic voltammetry was proposed. Linear relationship between values of oxidation peak current and concentration of p-benzenediol was kept in the range from 1.0×10-6 to 1.0×10-4mol·L-1, with detection limit (3S/N) of 4.0×10-7mol·L-1. The proposed method was used in the determination of p-benzenediol in simulated water sample, giving values of recovery and RSD (n=5) in the ranges of 95.3%-98.7% and 3.8%-4.2% respectively.