Conversion of waste biomass to valuable carbonaceous material is a sustainable and environmental benign method for energy and reduction of greenhouse gas emission. Herein, a two-step hydrothermal method was developed to fabricate high performance electrode material from pomelo peels. In the first step, the pomelo peels were transformed to carbonaceous aerogel (CA), which constructed of three-dimensional, sponge-like brown monolith with hierarchical pores, low-density (0.032g/cm) and excellent mechanical flexibility. Then, the cobalt nickel aluminum layered double hydroxide (CoNiAl-LDH) was in situ loaded on the surface of CA to form exquisite core-shell structure (CoNiAl-LDH@CA) through the second hydrothermal step. When used as an electrode material for supercapacitor, CoNiAl-LDH@CA exhibited high specific capacitances of 1,134F/g at 1A/g and 902F/g at 10A/g, respectively. Furthermore, they displayed an excellent cycling stability without an obvious capacitance decrease after 4,000 cycles.