Abstract: To improve the energy storage performance of MoO₃ as the supercapacitor electrode materials, the MoO₃ nanoribbon/reduced graphene oxide (RGO) composites were synthesized by one-step hydrothermal method. The phase structure, microstructure, and electrochemical properties of the composites were characterized by X-ray diffraction analysis, scanning electron microscopy, Fourier transform infrared spectroscopy, cyclic voltammetry curves, and constant current charge discharge curves. The results show that, the MoO₃ nanoribbon/RGO composites are successfully fabricated by the one-step hydrothermal method. Encouragingly, the specific capacitance of the composite materials is increased by 17.5%, compared with that of pure MoO₃ as 228 F∙g^‒1. Furthermore, the MoO₃ nanoribbons are wrapped by RGO or attached to the surface of RGO in the composites, enhancing the electrical conductivity and structure stability, and then improving the electrochemical performance.