A ternary nanocomposite of polypyrrole/molybdenum trioxide/graphene nanoribbon (PPy/MoO3/GNR) was successfully synthesized by using in situ oxidation polymerization method. The Fourier transform infrared (FTIR) spectra shows the metal oxide of MoO3 is successfully combined with GNR. The morphology is observed by using field emission scanning electron microscope (FESEM) and transmission electron microscopy (TEM). The electrochemical analysis, which is investigated by using electrochemical analysis instrument, shows the highest specific capacitance of 844 F g-1 and good cycle stability after 1000 cycles for PPy/MoO3/GNR ternary nanocomposite. These results demonstrate that the combination of each component can efficiently enhance the electrochemical capacity performance.