A nitrite sensor based on a gold particles/polyaniline modiﬁed glassy carbon electrode (Au/PAni/GCE) was devoped by electrochemical method. The electrocatalytic oxidation of nitrite at Au/PAni/GCE was studied by cyclic voltammetry. The experimental parameters were optimized, and a voltammetric method for determining nitrite was developed. In phosphate buffered solution(PBS) of pH 3.0, the oxidation peak current of nitrite is proportional to the concentration of nitrite over the range of 4.0×10-7～5.0×10-3mol/L with the detection limit of 2.0×10-7mol/L (r=0.9992). The presented methods of determing nitrite exhibited high sensitivity and good reproducibility.