The electrode material plays a key role in the performance of a supercapacitor. This study reports a method to prepare high conductivity hierarchical porous carbon with pre-crosslinking based on sodium lignosulfonate, which usually is burned as a waste effluent in pulp and paper mills. Results indicate pre-crosslinking with glutaraldehyde and ethyleneimine polymer, activation with less potassium hydroxide KOH, and finally carbonization to form carbon materials of hyperbranched macromolecules with ultra-rich specific surface area of 2780 m2/g and reasonable pore size distribution. The prepared carbon material showed high specific capacitance and good electrochemical performance when used as electrode materials for supercapacitors. At 0.5 A/g, the specific capacitance was 305 F/g, and the specific capacitance decay was only 6.2%, even after 2500 consecutive charge/discharge cycles, which revealed the huge potential for the supercapacitor characteristics with long service life. The results provided a high-valued application of industrial waste, which is important to further the sustainable development of the national economy.