The conversion of biomass waste into valuable carbon composites as efficient non-precious metal oxygen-reduction electrocatalysts is attractive for the development of commercially viable fuel-cell and metal-air battery technologies. Herein, a highly active and robust Si-contained Fe/N/C catalyst is prepared based on the porous carbon deriving from waste reed stalk after carbonization and KOH corrosion. Reed waste is a natural, abundantly available, and yearly renewable source, acting as the single precursor for Si containing-carbon substrate. The typical product (Si-Fe20/N/C1_6 in this work) possesses a high BET specific surface area, porous structure with high pyridinic-N and pyrrolic-N content. The X-ray absorption near edge structure (XANES), Raman, X-ray photoelectron spectroscopy (XPS) measurements and electrochemical measurements show that Si facilitates incorporation of more N to coordinate with Fe in the porous carbon and induces more graphitic carbon in the catalyst. The sample Si-Fe20/N/C1_6 exhibits better activity and superior stability than the Fe20/N/C counterpart and commercial Pt/C catalyst for the oxygen reduction reaction (ORR) in 0.1 M KOH electrolyte. The results suggest a promising route based on economical and sustainable biomass towards the development and engineering of value-added carbon materials as robust catalysts for oxygen reduction.