Abstract: Carbon assisted water electrolysis for hydrogen production usually added carbon sources (such as coal and biomass) into anode cell directly to form carbon slurry. This route always suffered from low current density due to the high mass transfer resistance between carbon particles and anode. The coal-based formcoke sacrificial anode was preparaed by co-forming and co-pyrolysis of coal, alkali-activated biomass and conductive graphite, and formcoke sacrificial anode was used in carbon assisted hydrogen production by water electrolysis. The efficiency of carbon assisted hydrogen production could be significantly improved at high current density (50 mA/cm²). The water electrolysis performance of formcoke sacrificial anode and its microstructure evolution were studied. Results showed the current density of formcoke sacrificial anode were 87 times higher than that of Pt anode at 1.23 V( vs. RHE), and the Tafel slopes also reduced by 41% compaired to that of Pt anode. The H₂ formation rate of formcoke sacrificial anode was 2.75 times than that of Pt anode at 50 mA/cm², while the potential of formcoke sacrificial anode was about 85% of Pt anode. The SEM, TGA, BET, FT-IR and XPS results showed that the sacrificial anode itself were oxidized during water electrolysis. Specifically the carboxyl C=O bond was oxidized to CO₂, and the content of C–O bond increased significantly. This research provide a new insight and reference for carbon assisted water electrolysis for hydrogen production.