Abstract: In order to obtain supercapacitor materials with high specific capacitance and good cycle life,The 3D-Fiberbased graphene (3D G) was prepared with a two-step carbonation by watermeon flesh as carbon source.At last CeO₂-MnO/3D G composite was prepared with the Hydrothermal method.The results show thatthe 3D G exhibits an excellent BET-surface area of 332 m²·g^-1 due to the good spatial structure.CeO₂-MnO/3D G composite are featured with a 3D conductive network structure,and metal oxide particles between the graphene sheets grow evenly,with about 10 nm in diameter.The electrochemical testing results show that the CeO₂-MnO/3D G composite exhibit an excellent capacitance of 308.5 F·g^-1 with the current density of 1 A·g^-1,MnO:CeO₂=4:1 and composite load at 80% in 0.5 mol·L^-1 Na₂SO₄ solution.Meanwhile,the CeO₂-MnO/3D G composite also show outstanding cycling stability with 95.5% of the capacitance retention after 1000 cycles of charge/discharge.The high electrochemical properties of the CeO₂-MnO/3D G composite is mainly attributed to the synergy of two metal oxide composite load with graphene.