The electrochemical polymerization of glutamic acid at the glassy carbon electrode was investigated in phosphate buffer solution by cyclic voltammetry. The applied voltage range, pH of electrolyte, cyclic number were explored for optimal polymerization conditions. The resulting film exhibits an electrocatalytic ability to hydrazine, reducing the overpotential by 500mV. The electrocatalytic response of hydrazine is evaluated with regard to pH, scan rate, applied voltage, hydrazine concentration and other variables. The rate constant of the catalytic reaction was 1.2 × 104M−1.s−1. When used as amperometric detector, the modified electrode yields a detection limit of 1 × 10−8M hydrazine. The electrode is rather stable even after use for a month and a reproducible response was obtained.