Abstract: A poly(L-threonine) modified electrode (PLTE) was fabricated by electrochemical immobilization of L-threonine on a glassy carbon electrode (GCE). The poly(L-threonine) layer exhibited superior electrocatalytic activity towards both dopamine (DA) and epinephrine (EP). The electrochemical behaviors of the modified electrode were explored in detail with cyclic voltammetry. The apparent electron transfer coefficient and standard rate constant were calculated to be 0.51 and 1.33 s-1, respectively, for the oxidation of EP in pH 2.5 phosphate buffer solution (PBS). The modified electrode exhibited a pair of redox peaks for the oxidation of DA in pH 7.5 PBS, the apparent electron transfer coefficient and standard rate constant were calculated to be 0.60 and 0.92 s-1, respectively. The cathodic peak currents were proportional to the concentration of DA and EP in the range of 1.0×10-6-5.0×10-4 mol·L-1 and 3.0×10-6-1.0×10-4 mol·L-1, respectively. This method was successfully applied for simultaneous determination of DA and EP.