Supercapacitors are highperformance energy storage devices with high power density, excellent cycling performance and highsafety. However, their low energy density limits their development. In order to further improve the energy density of supercapacitorsand meet the growing demand for energy storage, improving the electrochemical performance of electrode materials is the key. In order toimprove the electrochemical performance of fly ashbased manganese silicate/ manganese oxide, graphene oxide and fly ashbased manganese silicate/ manganese oxide composites were synthesized by electrostatic assembly method, and their electrochemical performance wasoptimized by adjusting the amount of graphene oxide added. The mechanism of the effect of graphene oxide on the electrochemical performance of fly ashbased manganese silicate/ manganese oxide was also studied. The morphology and structure of the materials were characterized by XRD, SEM, XPS and FTIR, and the properties of the materials and devices were tested by Cyclic Voltammetry, GalvanostaticChargeDischarge and Electrochemical Impedance Spectroscopy. The results show that the charge transfer rate of FA@ MS/ MO/ GO- 2is greatly improved after optimization, and FA@ MS/ MO/ GO-2 has a specific capacitance of 737.4 F/ g at a current density of 0.5 A/ g,which is higher than that of FA@ MS/ MO not compounded with graphene oxide(293.4 F/ g). FA@ MS/ MO/ GO-2 has the best capacityretention rate (67%) when the current density increases from 0.5 A/ g to 8.0 A/ g, which is higher than that of FA@ MS/ MO(44%). After FA@ MS/ MO/ GO-2 and commercial activated carbon are respectively assembled as positive and negative electrodes for asymmetric supercapacitors, the energy density of the device can reach 15.75 Wh/ kg (power density is 375 W/ kg), and the capacity retention rateand coulombic efficiency can reach 100% at 10 000 cycles at 5 A/ g, which shows that the electrode material has the potential of longtermrecycling and has a good practical application prospect.