BiOI microsquares was prepared by using hexamine as surfactant through solvothermal approach and used as electrode material for high performance supercapacitor. The crystalline structure and morphology of the BiOI were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) analysis. The electrochemical performance was investigated by using cyclic voltametry (CV) and galvanostatic charge-discharge studies (GCD) using 6M KOH solutions. BiOI electrode exhibits highest specific capacitance of 706Fg−1 at a current density of 2Ag−1. This material retained 55% initial capacitance at a higher current density of 10Ag−1 indicating its better rate performance.