Starting from the renewable biomass material palm kernel shell (PKS), nitrogen, sulfur and phosphorus co-doped high specific surface area porous activated carbon materials were prepared through carbonization and KOH chemical activation and applied to the supercapacitor electrode materials. PKS is a low-cost carbon source byproduct of biomass, which is rich in cellulose, lignin, and moisture, and its other components also provide nitrogen, sulfur, phosphorus and other heteroatoms for the final product. After further activation with different ratios of alkali and carbon, porous activated carbon (PAC) with different pore sizes could be obtained. The presence of heteroatoms not only provides redox pseudocapacitance, but doping heteroatoms is also beneficial to suppress irreversible changes of the oxygen-containing functional groups on the carbon material surface during the charging and discharging process. In 3 mol L⁻¹ KOH electrolyte solution, PAC showed an excellent electrochemical performance with good cycling stability, and its maximum specific capacity could reach 380 F g^−l.