In this study, we report a sensitive modified pencil graphite electrode prepared by easily coating with 3-amino-1,2,4-triazole-5-thiol (3AT5T) for the selective determination of 2-nitrophenol (2-NP) by differential pulse voltammetry (DPV) method. The electrochemical methods, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), were applied to characterize this modified electrode in the mixture of K-4[Fe(CN)(6)]/K-3[Fe(CN)(6)] containing 0.1 M KCl as redox probe. Further, the electrode was characterized by Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). PGE demonstrated a remarkable increment in the redox probes peak current, due to the effective electroactive surface area at the modified PGE (2.278 cm(2)) when it was compared with the bare PGE (0.128 cm(2)). This modified PGE was successfully used for the electrocatalytic reduction of 2-NP at pH 4.5 in 0.1 M phosphate (PBS) buffer. The reduction current response of 2NP at the modified PGE was increased at about 8 times compared with the bare PGE. From the DPV analysis, under the optimized conditions, the reduction peak currents were increased linearly with two concentration intervals of 2NP at pH 4.5 in PBS buffer. One of them is 45 nM-560 mu M and the other is 560 mu M-2 mM. The limit of detection (LOD) is found as 14.1 nM for 2-NP (S/N = 3). The fabricated PGE was tested in water samples for the practical utilization. From the results, it was pointed that the modified PGE can be used as an environmental sensor in analytical applications.