A SeO2 nanostructure was prepared employing stabilized solvothermal method for water oxidation process in three electrodes cell set-up. Reducing agent influence on material morphology and its domination on electrochemical properties were investigated. Tetragonal structure of SeO2 was confirmed from the crystal plane of (211) through X-ray diffraction (XRD) study. Reducing agent concentration was highly dominated the particle size and shape which was explored by field emission scanning electron micrograph (FESEM) images. The superior electrochemical specific capacitance of 572 F/g at 10 mV/s was afforded by SeO2 nanoparticles synthesized via 15 M NaBH4 by cyclic voltammogram (CV) study. The highest water oxidation performance of 292 mA/g at 10 mV/s was also demonstrated by the same electrode from linear sweep voltammogram (LSV), with better charge transfer and excellent stability. The exceptional performance of the SeO2 electrocatalyst prepared by using highest NaBH4 concentration evidenced its great role for potential applications.