Abstract: To improve the energy storage performance of MoO3 as a supercapacitor electrode material，MoO3/RGO composites were synthesized by one-step hydrothermal process. The phase structure, morphology and electrochemical properties of the materials were characterized by XRD, SEM, FTIR, cyclic voltammetry, constant current charge discharge, and the effect of hydrothermal process on the microstructure and electrochemical properties of the composites was explored. The results showed that the MoO3 nanoribbons/RGO composites were successfully fabricated by a one-step hydrothermal method. Encouragingly, the specific capacitance of composite material was increased by 17.5% compared with that of pure MoO3 (228 F.g-1). Furthermore, the MoO3 nanoribbons were wrapped by RGO or attached to the surface of RGO in the composite, which induced obvious enhancement of the electrical conductivity as well as the structure stability, and subsequently the ultimate electrochemical properties of the original materials.