Abstract:  Hydrogen production performance of a membrane-less bio-electrochemically assisted microbial reactor was studied in this paper. Membrane-less microbial reactor consisted of carbon felt as anode, carbon plate supported by self-made Ni-Al-Sn alloy powders(Ni-50%,Al-45%,Sn-5%) as cathode and acetate as electrolyte for generating hydrogen. Its principle was that the organic was degraded by microbe to produce electron and protons in the anode chamber, and then protons arriving at cathode got electron and generated hydrogen through an applied voltage between two electrodes of membrane-less microbial reactor. The influences of carbon felt amount used for the anode, environment temperature, and applied voltage, etc. on hydrogen production rate and hydrogen selectivity were studied. And the optimal results demonstrated that the rate of hydrogen production reached at 4.21m³/(d·m³) and the highest hydrogen selectivity was 70.4% when the anode surface area was 900cm², the environment temperature was 30℃ and the applied voltage was 0.9V.