Copper nano-clusters were electrodeposited onto the platinum microelectrode by cyclic voltammetry method to fabricate an electrochemical sensor for nitrate determination. The material properties and morphologies of freshly deposited copper layer were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. Compared with the microelectrode surface modified by fixed potential deposition method, the surface modified by cyclic voltammetry electrodeposition is porous and has a larger effective surface area. The reduction of nitrate under acidic conditions (pH=2) was characterized by linear sweep voltammetry. The preliminary experimental results reveal that the microelectrode modified by cyclic voltammetry electrodeposition had higher sensitivity of 22.56 uA/mmol for nitrate detection within the concentration range from 0.1mmolL−1 to 4mmolL−1.