In this work, we present a facile approach to synthesize nitrogen-doped porous carbon materials via a two-step fabrication process using the stem bark of broussonetia papyrifera (BP) as the biomass precursor. Firstly, the BP stem bark is hydrothermally treated in a KOH aqueous solution. After filtration and drying, the hydrothermal product is directly subjected to simultaneous pyrolysis and activation, giving nitrogen-doped porous carbon materials. The morphology, structure and textural properties of the carbon materials are investigated by scanning electron microscopy, transmission electron microscopy, N2 sorption isotherms, and X-ray photoelectron spectroscopy. The obtained porous carbon exhibits a high BET surface area of 1212m2 g−1 and an average pore size of 3.8nm. Such porous carbon shows outstanding capacitive performance (320Fg−1 at 0.5Ag−1), good rate capacitive behavior, and excellent cycling stability due to the synergistic effect of N, O-doped species, indicating a great potential for supercapacitors.