A coral-like polyaniline/activated biocarbon (PANI/AB) composites were prepared via in-site polymerization method. First, the activated biocarbon (AB) was derived from sugarcane bagasse, and then, the PANI/AB composites were obtained using AB as the scaffolds for PANI growth and [CMMIm]Cl ionic liquid as dopant. The results indicated that chemical composition and microstructure of PANI/AB were closely related to the mass ratio of aniline monomer (An) and AB, and which further impacted electrochemical performance of PANI/AB profoundly. Especially, the PANI/AB-4 (the mass ratio of An/AB is 40) exhibited a highest specific capacitance of 447 F g(-1) at a current density of 0.5 A g(-1). Furthermore, the asymmetric two-electrode system based on PANI/AB-4 as positive electrode and AB as negative electrode is successfully assembled with a voltage window of 0-1.6 V, exhibiting high energy density (27.3 Wh kg(-1)) and power density (800 W kg(-1)), and excellent cycling stability (87% capacitance retention after 2000 cycles).