Selective fabrication of carbon materials with developed specific surface area and hierarchical porous structure is essential for high-performance carbon-based supercapacitors. Direct carbonization of organic acid salts represents a strategy that can produce porous carbon with high specific surface area, but it is still hindered by low carbon yield, impeding its large-scale application. Herein, a biomass-derived hierarchical porous carbon with large specific surface area is prepared via a facile one-pot calcination method. The optimal SCPC-4 sample presents three-dimensional interconnected network structure and plentiful heteroatom content. Hence, it delivers a large specific capacitance of 321 F g−1 at a current density of 1 A g−1, and negligible capacitance loss after 10,000 cycles at 10 A g−1. In addition, the assembled SCPC-4 based symmetric supercapacitor exhibits an energy density of 21.2 Wh kg−1 at a power density of 900 W kg−1. This cost-effective binary biomass carbon source route provides a great possibility for the mass production of high-yield porous carbon materials.