NOVELTY - A two-step biological hydrogen producing method of organic waste comprises screening anaerobic active sludge from methane tank or pool or sewage treatment plant, mixing pretreated material and anaerobic fermentation hydrogen producing bacteria, and subjecting to anaerobic hydrogen producing reactor for 12-72 hours while controlling pH value at 4.5-6.5 to generate organic acid, hydrogen and carbon dioxide; and separating hydrogen and carbon dioxide, and discharging organic acid containing waste from anaerobic hydrogen producing reactor.    USE - A two-step biological hydrogen producing method of organic waste (claimed).    ADVANTAGE - The method has improved yield and improved energy recycling rate.    DETAILED DESCRIPTION - A two-step biological hydrogen producing method of organic waste comprises:    (A) screening anaerobic active sludge from methane tank or pool or sewage treatment plant, mixing pretreated material and anaerobic fermentation hydrogen producing bacteria, and subjecting to anaerobic hydrogen producing reactor for 12-72 hours while controlling pH value at 4.5-6.5 to generate organic acid, hydrogen and carbon dioxide;    (B) separating hydrogen and carbon dioxide, and discharging organic acid containing waste from anaerobic hydrogen producing reactor;    (C) mixing waste and anaerobic electricity generating bacteria, and subjecting to anode chamber of a microbial electrolysis cell controlled at under anaerobic condition to form carbon dioxide, proton and electron; and    (D) passing proton through a proton exchange film and cathode chamber of a microbial electrolysis cell, delivering electron to cathode electrode of cathode chamber from anode electrode to generate proton under catalytic action of cathode electrode and recycling and discharging of clean water.    An INDEPENDENT CLAIM is included for two-step biological hydrogen producing device comprising a feed bin; an anaerobic hydrogen producing reactor having a feed port, a discharge hole, a top water distributor, a pore plate, a penetrating filler, an air outlet and a sludge outlet; and a microbial electrolysis cell divided into an anode chamber and a cathode chamber.    DESCRIPTION OF DRAWING(S) - The drawing is a flow chart of a two-step biological hydrogen producing method of organic waste. Drawing includes non-English language text.